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#21
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On Sat, 30 Aug 2003 18:29:30 -0400, "Timothy Drouillard"
wrote: 36gig WD Raptor how many points you get with Sandra Disk bench? (just curious) -- Regards, SPAJKY & visit - http://www.spajky.iscyber.com Celly-III OC-ed,"Tualatin on BX-Slot1-MoBo!" E-mail AntiSpam: remove ## |
#22
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kony wrote:
On Sat, 30 Aug 2003 21:49:12 GMT, TC wrote: /\/\/\/\ Actually .. the ducted fan is state of the art. Nope, Gateway, Compaq and others have been using passive coolers and ducts since the Pentium 1 days. True. Different designs, however. The CPU runs hotter as a result, then and today. Not so. It is not 'because' of the ducted design. It because their design goal, regardless of the chosen cooling method, is proper operation within the temperature specs and not 'the coolest we can get it'. Ductwork is merely cheaper than a high-quality heatsink, Again, not necessarily so. Depends on the overall design. which would keep the CPU cooler AND be as quiet. Simply not possible. HSF assembly gets it's air from and discharges it's hot air into the case, which then needs to be ventilated more than if that hot air were immediately expelled (as it is in the ducted design). The result is more fans (or fan speeds) and more noise for the equivalent cooling. The other benefit is that these systems are being shipped, sometimes great distances under less-than-ideal conditions, so reduced heatsink weight as on the Dells is reducing the chance of RMA due to socket or CPU damage. Odds are the 'passive' (it's not really passive; the fan is just located differently) heatsink is as massive, perhaps more, than one with the fan mounted on it. It depends on the design if removal of the fan compensates but it isn't a foregone conclusion. Proper fan selection is crucial to achieve low noise on an active heatsink, but so it was also when Dell built their ducted system. True. The point is, by ducting the hot CPU air directly out of the case, rather than mixing it in as a HS mounted one does, there is less work needed to cool the system. |
#23
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I agree. Why do people pay good money for an expensive product, then allow
an in-warranty defect to befuddle them. I assume this is a new box (the 8300 hasn't been around long). So if it's in warranty, let Dell sort it out (or take it back!). Anyway, 60-70 C is frying hot. (That's 140-158 F for us Americans). Normal temps run in the mid- to high-30s. Something is very wrong. "FatAntKnee" wrote in message . 7... A 8300 should still be under warranty barring any mods you made to the case. It should not overheat, if it does then it sounds like an issue that Dell needs to resolve. |
#24
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"drumguy1384" wrote in message ... "TC" wrote in message ... "127.0.0.1" wrote in ink.net: thats a poor design. i would purchase a quality HS + Fan and remove that case fan. if there are other case fans to move the air, it should be sufficient. or put a smaller fan to replace that obstrusive case fan. there are other options on circulating the case. but the most important part of your problem is getting a proper HS + fan installed. It really makes you wonder if this guy thinks that Dell is "cutting costs" by engineering new cooling solutions for each new system they come out with. A duct cooling system involves a custom heatsink, and a custom duct housing which has to be changed for every new system model. I would think that just plonking a decent CPU "HS/fan" type cooler on there would be much easier, and cheaper. Why then re-invent the wheel with each new model? Obviously ... because it WORKS BETTER! Get a clue 127! And TC, thank you for saying what I had been itching to since the first ignorant post I saw from this guy. Drumguy stay on topic please. Original Poster (OP) needs help with his overheating problem, not a debate on how well dell designs their mass produced products. Drumguy still has yet to post a solution. i gave my suggestion on adding a new Heat Sink (HS) + fan. what has Drumguy suggest? leave it alone because it shouldn't be overheating? that's not a solution. i'm not the type to lecture someone who needs help. if i can fix it, then i will. will i teach that person the physics involved in locating the cause of the problem? not for free. i may be ignorant, but at least i'm polite. my last post on this thread... |
#25
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On Sun, 31 Aug 2003 05:37:03 -0500, David Maynard
wrote: kony wrote: On Sat, 30 Aug 2003 21:49:12 GMT, TC wrote: /\/\/\/\ Actually .. the ducted fan is state of the art. Nope, Gateway, Compaq and others have been using passive coolers and ducts since the Pentium 1 days. True. Different designs, however. The CPU runs hotter as a result, then and today. Not so. It is not 'because' of the ducted design. It because their design goal, regardless of the chosen cooling method, is proper operation within the temperature specs and not 'the coolest we can get it'. The issue is not one of achieving "the coolest we can get it", but rather noise/heat ratio, that a duct impedes exhaust, making the rear fan noiser at the same exhaust flow rate. To keep the CPU at the same (high) operating temp as in the Dell ducted system, a good active cooler's fan can run at low enough RPM, low enough turbulence, that what litte noise it creates, being buffered by the enclosure, is less audible than the increase in ducted exhaust fan noise. Running the rear fan at higher RPM is necessitated by the duct, else there is more heat buildup in the system. The total system heat generation can be considered constant so the total airflow through the system must also remain the same else the Dell system runs hotter in more areas than just the CPU. Lower air intake into the system will then result in hotter air entering the heatsink. Proper operation within the temperature spec (instead of lowest possible CPU temp) is the notion that allows using a low-RPM fan on the heatsink instead of the noisey fans most people compare to the Dell ducted system. If we are considering a custom-designed OEM cooling system it has to be compared to an active cooling stategy with similar forethought, not just a cheap/junk $5 'sink with a tornado-speed fan on top. Ductwork is merely cheaper than a high-quality heatsink, Again, not necessarily so. Depends on the overall design. There are a lot of variables involved with design, production, parts, but in general a high-volume production piece of plastic should be less costly than a second fan and more elaborate heatsink. There can be exceptions but practically we can only consider the ducted systems being used by OEMs, not theorectical, nonexistant systems. A ducted cooling system does tend to be the best noise/heat ratio if there are budget constraints, at least for an OEM who can buy in bulk. In other words, it can be the best budget-optimized solution for an OEM, but optimizing as much as possible for cooling or noise, a ducted passive 'sink cooling system cannot attain as low a noise/heat ratio. Combining the two strategies, having a duct AND an active cooler, would be the choice for lowest temps but again the duct necessitates an increase in noise else *something* will run hotter, and of course it will tend to be the most expensive alternative. which would keep the CPU cooler AND be as quiet. Simply not possible. HSF assembly gets it's air from and discharges it's hot air into the case, which then needs to be ventilated more than if that hot air were immediately expelled (as it is in the ducted design). The result is more fans (or fan speeds) and more noise for the equivalent cooling. It is possible with a high-quality active cooler. Even though some heated air is recirculated the primary source of audible noise in an optimized configuration is the rear fan, which is less efficient with a duct on it. By optimizing both methods there might be similar noise/heat ratios, but then the ducted system is more dependent on preservation of the chassis airflow model. The other benefit is that these systems are being shipped, sometimes great distances under less-than-ideal conditions, so reduced heatsink weight as on the Dells is reducing the chance of RMA due to socket or CPU damage. Odds are the 'passive' (it's not really passive; the fan is just located differently) heatsink is as massive, perhaps more, than one with the fan mounted on it. It depends on the design if removal of the fan compensates but it isn't a foregone conclusion. Passive 'sinks are usually less densely populated with fins and have a greater percentage of weight at their base, which is less leveraged force against the socket or retention mechanism. Proper fan selection is crucial to achieve low noise on an active heatsink, but so it was also when Dell built their ducted system. True. The point is, by ducting the hot CPU air directly out of the case, rather than mixing it in as a HS mounted one does, there is less work needed to cool the system. Possibly, not not necessarily, and work is not always directly related to _audible_ noise. Increasing the work done by a single fan by having it create a suction through a duct, requires higher RPM, enough so that the fan is no longer as quiet as the audible sum of [that fan at lower RPM & turbulence, same airflow rate without duct] + [fan on heatsink keeping CPU at same temp]. We could argue that a highly optimized (per system) duct be used, but it would then need be compared to an optimized active 'sink, and the optimized duct would be even less forgiving of user modifications to the system, which must be considered on a PC. Dave |
#26
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Well, I now own 5 Dells at home with that "bad design".
Where I work, there are about 2500 more of them. This "bad design" has not caused problems. "127.0.0.1" wrote in message ink.net... "Timothy Drouillard" wrote in message ... It's not nessarily a 'bad' design, just a different one. Dell does it that way on purpose. That way, by using a large finned heat-sink on the CPU along with a duct to dirrect the airfow to/from the fan on the rear of the case, they have enough room on the back of the case to use a larger fan. A larger fan can spin at a slower RPM yet give as much airflow as a faster small fan directly on the heat-sink. A slower fan translates into less fan noise, making the system in theory, quiter, which in importatnt to many customers. a choice of quieter with overheating vs. a bit noisier with efficient cooling.... they are still years behind macintosh designs (cube). i forget what the original processor is. but having no fan on a cpu HS is not a good design. i'd rather see the dell executives cut their bonuses to save on cost than skimping out on proper cpu cooling. |
#27
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kony wrote:
On Sun, 31 Aug 2003 05:37:03 -0500, David Maynard wrote: kony wrote: On Sat, 30 Aug 2003 21:49:12 GMT, TC wrote: /\/\/\/\ Actually .. the ducted fan is state of the art. Nope, Gateway, Compaq and others have been using passive coolers and ducts since the Pentium 1 days. True. Different designs, however. The CPU runs hotter as a result, then and today. Not so. It is not 'because' of the ducted design. It because their design goal, regardless of the chosen cooling method, is proper operation within the temperature specs and not 'the coolest we can get it'. The issue is not one of achieving "the coolest we can get it", but rather noise/heat ratio, that a duct impedes exhaust, making the rear fan noiser at the same exhaust flow rate. To keep the CPU at the same (high) operating temp as in the Dell ducted system, a good active cooler's fan can run at low enough RPM, low enough turbulence, that what litte noise it creates, being buffered by the enclosure, is less audible than the increase in ducted exhaust fan noise. Running the rear fan at higher RPM is necessitated by the duct, else there is more heat buildup in the system. Nice theory but not true. Case temp is cooler because the heat is directly exhausted rather than circulated. You also fail to take into account that the Dell motherboard is designed with the CPU socket located to minimize duct air impedance. The total system heat generation can be considered constant so the total airflow through the system must also remain the same else the Dell system runs hotter in more areas than just the CPU. Directly exhausting the heat requires less airflow than first mixing it then exhausting it. Plus it results in cooler air into the heatsink because the case air is cooler: not being first preheated with the heatsink exhaust. Lower air intake into the system will then result in hotter air entering the heatsink. There isn't necessarily lower air intake into the system but it could be as it's easier to cool the remaining components when you don't have the CPU heat being vented into the case. Proper operation within the temperature spec (instead of lowest possible CPU temp) is the notion that allows using a low-RPM fan on the heatsink instead of the noisey fans most people compare to the Dell ducted system. True, but no fan is still less noise than a 'low noise' fan. If we are considering a custom-designed OEM cooling system it has to be compared to an active cooling stategy with similar forethought, not just a cheap/junk $5 'sink with a tornado-speed fan on top. No fan is still less noise than a 'low noise' fan and, with your active HSF, you STILL need the case fan; with more airflow because it has more volume to get rid of. Ductwork is merely cheaper than a high-quality heatsink, Again, not necessarily so. Depends on the overall design. There are a lot of variables involved with design, production, parts, but in general a high-volume production piece of plastic should be less costly than a second fan and more elaborate heatsink. It's your assumption than an active heatsink is necessarily "more elaborate" for the same cooling that I dispute. There can be exceptions but practically we can only consider the ducted systems being used by OEMs, not theorectical, nonexistant systems. A ducted cooling system does tend to be the best noise/heat ratio if there are budget constraints, at least for an OEM who can buy in bulk. It's also the best technical noise/heat solution between the two regardless of cost. It's simply a more efficient use of the airflow. In other words, it can be the best budget-optimized solution for an OEM, but optimizing as much as possible for cooling or noise, a ducted passive 'sink cooling system cannot attain as low a noise/heat ratio. I have no idea what makes you think that simply recirculating hot CPU air inside the case, rather than expelling it, is 'better'. Ducting CPU heat out is inherently a better cooling/noise solution. Combining the two strategies, having a duct AND an active cooler, would be the choice for lowest temps but again the duct necessitates an increase in noise else *something* will run hotter, and of course it will tend to be the most expensive alternative. You simply refuse to recognize the benefit of expelling the heat directly rather than first mixing it with case air and then having to expel the entire case volume to remove it. You don't NEED the same airflow to remove the heat if it goes directly out. Not to mention one can use larger, quieter, fans on the rear mount than can be shoved into the socket footprint. which would keep the CPU cooler AND be as quiet. Simply not possible. HSF assembly gets it's air from and discharges it's hot air into the case, which then needs to be ventilated more than if that hot air were immediately expelled (as it is in the ducted design). The result is more fans (or fan speeds) and more noise for the equivalent cooling. It is possible with a high-quality active cooler. I don't care HOW 'quality' your active cooler is; it's still dissipating the CPU heat INTO the case and not OUT of the case. And after you've dumped the CPU heat into the case with an active HSF you STILL have to have a case fan to expel it. Even though some heated air is recirculated the primary source of audible noise in an optimized configuration is the rear fan, which is less efficient with a duct on it. You have to expel the heat sooner or later and it takes less airflow if the CPU heat is vented directly instead of having to expel the entire case volume to get rid of it. By optimizing both methods there might be similar noise/heat ratios, but then the ducted system is more dependent on preservation of the chassis airflow model. 'Preserving' the 'chassis airflow model'? What then heck does that mean? The chassis has to be ventilated regardless. MORE so if you dump the CPU heat into it. The other benefit is that these systems are being shipped, sometimes great distances under less-than-ideal conditions, so reduced heatsink weight as on the Dells is reducing the chance of RMA due to socket or CPU damage. Odds are the 'passive' (it's not really passive; the fan is just located differently) heatsink is as massive, perhaps more, than one with the fan mounted on it. It depends on the design if removal of the fan compensates but it isn't a foregone conclusion. Passive 'sinks are usually less densely populated with fins and have a greater percentage of weight at their base, which is less leveraged force against the socket or retention mechanism. Whether true or not it's not a passive heatsink. The fan is just located in a different spot. Proper fan selection is crucial to achieve low noise on an active heatsink, but so it was also when Dell built their ducted system. True. The point is, by ducting the hot CPU air directly out of the case, rather than mixing it in as a HS mounted one does, there is less work needed to cool the system. Possibly, not not necessarily, and work is not always directly related to _audible_ noise. Increasing the work done by a single fan by having it create a suction through a duct, requires higher RPM, enough so that the fan is no longer as quiet as the audible sum of [that fan at lower RPM & turbulence, same airflow rate without duct] + [fan on heatsink keeping CPU at same temp]. Doesn't need the same airflow over the CPU heatsink as the heatsink is operating with cooler case air, since it's not preheated with the exhaust from the CPU. Plus it's venting the case in addition to whatever case cooling you'd require when dumping CPU heat into the case. We could argue that a highly optimized (per system) duct be used, but it would then need be compared to an optimized active 'sink, and the optimized duct would be even less forgiving of user modifications to the system, which must be considered on a PC. "Optimized" is precisely what an active HSF is not. It's the 'norm' for generic systems because one cannot make any assumptions about the system design: I.E. what else is in it and where anything is located. You can't count on there even being a rear exhaust port or, if it exists, that it's located where a 'standard' duct (that doesn't exist) would lead to, not to mention you don't know the exact location of the socket as that is left open, within reason, to the motherboard designer. But you CAN just slap an active HSF on it and then leave case cooling to someone else; with the typical solution being to slap gaggles of fans everywhere to 'cool' it. |
#28
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"127.0.0.1" wrote in message link.net... "drumguy1384" wrote in message ... "TC" wrote in message ... "127.0.0.1" wrote in ink.net: thats a poor design. i would purchase a quality HS + Fan and remove that case fan. if there are other case fans to move the air, it should be sufficient. or put a smaller fan to replace that obstrusive case fan. there are other options on circulating the case. but the most important part of your problem is getting a proper HS + fan installed. It really makes you wonder if this guy thinks that Dell is "cutting costs" by engineering new cooling solutions for each new system they come out with. A duct cooling system involves a custom heatsink, and a custom duct housing which has to be changed for every new system model. I would think that just plonking a decent CPU "HS/fan" type cooler on there would be much easier, and cheaper. Why then re-invent the wheel with each new model? Obviously ... because it WORKS BETTER! Get a clue 127! And TC, thank you for saying what I had been itching to since the first ignorant post I saw from this guy. Drumguy stay on topic please. Original Poster (OP) needs help with his overheating problem, not a debate on how well dell designs their mass produced products. Drumguy still has yet to post a solution. i gave my suggestion on adding a new Heat Sink (HS) + fan. what has Drumguy suggest? leave it alone because it shouldn't be overheating? that's not a solution. i'm not the type to lecture someone who needs help. if i can fix it, then i will. will i teach that person the physics involved in locating the cause of the problem? not for free. i may be ignorant, but at least i'm polite. my last post on this thread... Hey man, don't get me wrong. I'm not saying that a new cooling solution isn't what he needs ... but you said that the duct system is inferior in design to a conventional HS/Fan solution. I was merely disagreeing with you. I was not attempting to solve the OTP's problem ... only to take issue with your insinuations about the effectiveness of a duct cooler. But, since you insinuate that because I didn't tell him what I would do that I don't have a solution I'll get to it shortly. Shall I quote you? "thats a poor design." "having no fan on a cpu HS is not a good design. i'd rather see the dell executives cut their bonuses to save on cost than skimping out on proper cpu cooling." That's pretty inflammatory language there ... and hardly polite. I was simply pointing out that you are wrong to say that a duct cooling system is worse than a traditional HS/Fan solution. Sure, there are many aftermarket coolers that will do a better job of cooling his CPU ... but unless you find one with a 120mm fan (as his duct fan is) anything he get's will be louder. Of course I agree that a bit louder and stable is better than quiet and unstable. But his heat problem may be easily curable by blowing any dust out of the heatsink fins and/or re-applying it using some high quality thermal paste, such as Arctic Silver III. It may also be that the fan in his duct system is crapping out ... which can and does happen, especially if it's left on all the time. In which case, if it can't be replaced independently of the duct, it'd be best to remove the duct system and use a conventional cooler and another quiet 120mm case fan in the back without the housing. However, if the fan is the culprit and it's not permanently affixed to the duct then the best course of action would be to replace it with another 120mm fan and leave the duct in place. The truth is that this cooling solution works just fine in every system it's used in ... and it wouldn't continue to be used it if didn't work. Either it's crammed up with dust or the fan is crapping out. Simple as that. Your first course of action was to can the whole cooling system and replace it with a louder conventional system ... because it was, in your opinion, "a poor design." I just submit that may not be necessary, and that he may do better to try and salvage what he's got. He would end up with an adequate cooling system that is as quiet as it's ever been, and keeps his CPU quite cool enough. Good enough for ya? Drumguy |
#29
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On Sun, 31 Aug 2003 22:14:41 -0500, David Maynard
wrote: The issue is not one of achieving "the coolest we can get it", but rather noise/heat ratio, that a duct impedes exhaust, making the rear fan noiser at the same exhaust flow rate. To keep the CPU at the same (high) operating temp as in the Dell ducted system, a good active cooler's fan can run at low enough RPM, low enough turbulence, that what litte noise it creates, being buffered by the enclosure, is less audible than the increase in ducted exhaust fan noise. Running the rear fan at higher RPM is necessitated by the duct, else there is more heat buildup in the system. Nice theory but not true. Case temp is cooler because the heat is directly exhausted rather than circulated. You also fail to take into account that the Dell motherboard is designed with the CPU socket located to minimize duct air impedance. Anyone with a Dell system can open their system, feel the heatsink, and know that it is true. The CPU socket location does minimize the impact, but that impact is still a great reduction in airflow. Reduced airflow results in higher heat retention, there's no fancy combination of ducting theories that changes that. I'm not suggesting that Dell systems usually run hot enough to be instable, but neither do other equally thought out, quiet systems. The total system heat generation can be considered constant so the total airflow through the system must also remain the same else the Dell system runs hotter in more areas than just the CPU. Directly exhausting the heat requires less airflow than first mixing it then exhausting it. Yet there is less airflow, significantly less going though the heatsink, enough less that even a percentage of recirculated air on an active cooler keeps the CPU at lower temp. The goal is not to reduce airflow, to get the maximual cooling benefit from each CFM of airflow, or rather it shouldn't be. The goal should be maximal cooling benefit from each db of noise, and give the system tolerance to user alteration, component additions, etc. Plus it results in cooler air into the heatsink because the case air is cooler: not being first preheated with the heatsink exhaust. Reduction in intake airflow (if the ducted system is operating with rear fan at same noise level) causes the air to become more heated on it's way to the duct. Heat can't magically escape... given a radiation rate the airflow rate dictates total heat retention over ambient external room temp. No matter how great the duct is, it reduces airflow, which increases heat retention. Lower air intake into the system will then result in hotter air entering the heatsink. There isn't necessarily lower air intake into the system but it could be as it's easier to cool the remaining components when you don't have the CPU heat being vented into the case. There IS necessarily lower air intake. It is impossible to add a duct to the rear fan and have the same exhaust rate, same intake rate as before it's addition, unless the fan is operated at higher RPM, which is louder, and of course increases airflow on the ductless system further. Proper operation within the temperature spec (instead of lowest possible CPU temp) is the notion that allows using a low-RPM fan on the heatsink instead of the noisey fans most people compare to the Dell ducted system. True, but no fan is still less noise than a 'low noise' fan. Not true from a user's perspective. Fans mounted on the chassis allow a far greater percentage of sound to escape the chassis. The increase in rear fan noise to attain same airflow as a ductless cooling system, is audibly lower to the user than the heatsink fan running at low RPM. If we are considering a custom-designed OEM cooling system it has to be compared to an active cooling stategy with similar forethought, not just a cheap/junk $5 'sink with a tornado-speed fan on top. No fan is still less noise than a 'low noise' fan and, with your active HSF, you STILL need the case fan; with more airflow because it has more volume to get rid of. Noise is not additive, two lower RPM fans are usually quieter than one higher RPM fan, particularly when the higher RPM fan is mounted on the wall of the chassis, and even further the higher-pitch of the higher-RPM rear fan is more noticeable to human ears. I will mention again that proper fan selection is crucial. There are a lot of variables involved with design, production, parts, but in general a high-volume production piece of plastic should be less costly than a second fan and more elaborate heatsink. It's your assumption than an active heatsink is necessarily "more elaborate" for the same cooling that I dispute. I could likewise dispute that a passive cooler is more elaborate than an equally well-designed active cooler. Actually I feel the opposite, that it takes a much more elaborate and expensive passive cooler to come anywhere near the cooling efficiency of a cheap, low-end active cooler. The problem is, they generally aren't more elaborate when comparing to a good active cooler, not mid-to-low end. Which should cost more to produce in volume? Granted there are some really junky fans that may hardly be worth the plastic they're made out of from a reliability or noise standpoint, but instead considering a fan of similar quality to the rear fan, the main issue would be volume production. Since fans are already produced in volume, production lines are in place to produce them regardless of what Dell is doing. If Dell buys enough ducts they're going to be even more inexpensive, and since these are likley supplied by the case manufacturer it may be a "free" duct. I don't recall any case manufacturers providing free heatsink fans ecxept in rare cases like thoose miniature Shuttle systems or similar where space constraints make a specific heatsink size necessary. There can be exceptions but practically we can only consider the ducted systems being used by OEMs, not theorectical, nonexistant systems. A ducted cooling system does tend to be the best noise/heat ratio if there are budget constraints, at least for an OEM who can buy in bulk. It's also the best technical noise/heat solution between the two regardless of cost. It's simply a more efficient use of the airflow. A ducted passive cooling system is a more efficient use of a given CFM, but it's not like there's only "X" amount of airflow allowed, rather the primary issue is usually noise. Introducing the duct causes a significantly lower CFM to noise ratio. It's unavoidable with an axial fan. In other words, it can be the best budget-optimized solution for an OEM, but optimizing as much as possible for cooling or noise, a ducted passive 'sink cooling system cannot attain as low a noise/heat ratio. I have no idea what makes you think that simply recirculating hot CPU air inside the case, rather than expelling it, is 'better'. Recirculating airflow isn't better than not recirculating, but since that's not the only issue it has to be weighed against others, like total airflow, and a greater airflow though the CPU 'sink. The greater the airflow though the CPU 'sink on a passive cooler (given an optimal duct for that purpose) the greater the reduction in exhaust, and intake airflow. Moving the opposite direction, reducing backpressue by diverting less air through the CPU 'sink will somewhat increase chassis airflow, but the CPU runs hotter. Ducting CPU heat out is inherently a better cooling/noise solution. Combining the two strategies, having a duct AND an active cooler, would be the choice for lowest temps but again the duct necessitates an increase in noise else *something* will run hotter, and of course it will tend to be the most expensive alternative. You simply refuse to recognize the benefit of expelling the heat directly rather than first mixing it with case air and then having to expel the entire case volume to remove it. You don't NEED the same airflow to remove the heat if it goes directly out. At the same airflow rate it is of benefit to remove the heated air as directly as possible. At a greater airflow rate the benefit of it is quickly overcome. Higher exhaust rate also reduces mixing of heated air, reduces the pre-heating of air from other components prior to reaching the CPU heatsink. Not to mention one can use larger, quieter, fans on the rear mount than can be shoved into the socket footprint. The size of rear fan is a constant, since the same chassis can be used for either cooling configuration. Given this same sized fan, it will produce more noise at same flow rate OR same noise at lower flow rate with a duct on it. A fan mounted on the CPU heatsink need not be as large as the case fan, will move a lot more air through the heatsink due to proximity, because axial fans cannot create significant pressure. It is possible with a high-quality active cooler. I don't care HOW 'quality' your active cooler is; Perhaps this is why you haven't seen the same results. Passive coolers don't even come close, not with a duct, not with a 120mm fan. They usually provide just enough margin to operate stabily, little more than that. it's still dissipating the CPU heat INTO the case and not OUT of the case. A great portion of the CPU exhaust from an active cooler is directly removed, especially with a 120mm fan. And after you've dumped the CPU heat into the case with an active HSF you STILL have to have a case fan to expel it. So you don't really care about performance, you're just opposed to using two fans? Even though some heated air is recirculated the primary source of audible noise in an optimized configuration is the rear fan, which is less efficient with a duct on it. You have to expel the heat sooner or later and it takes less airflow if the CPU heat is vented directly instead of having to expel the entire case volume to get rid of it. The system 'creates' a given amount of heat. There is no duct that changes that. The lower the exhaust rate, the hotter the air is... nothing changes that either. The ducted system has lower exhaust rate at same noise level, because of the duct... exactly what this duct does, concentrate and redirect airflow, is exactly why it reduces airflow. It can't be argued that all this air was heated passing through the heatsink on it's way out because with less cool intake air the rest of the components are hotter, heat the intake air more. Many such ducted systems even feel noticably warm on the outside, a clear indication that ambient temps are quite high. By optimizing both methods there might be similar noise/heat ratios, but then the ducted system is more dependent on preservation of the chassis airflow model. 'Preserving' the 'chassis airflow model'? What then heck does that mean? The chassis has to be ventilated regardless. MORE so if you dump the CPU heat into it. Dell (and others) have to move a cetain amount of airflow through that CPU heatsink, and likewise in other areas of the chassis. At a bare minimum I'll bet they want it to last until the warranty is expired. This is an engineered cooling system to achieve the desired result, not just the duct but the whole chassis... The proposed solution is an environmental model of an actual system, before it ever goes into production. If the intake, exhaust, or flow pattern is altered, the target temps deviate from the model. Our OP, Peter, may be experiencing exactly that when he added the exhaust fan for his video card, which reduces exhaust though the duct even further. He might see improvement by using an intake fan, except that I dont' recall seeing any slot-mounted intake fans, but if there are any... Passive 'sinks are usually less densely populated with fins and have a greater percentage of weight at their base, which is less leveraged force against the socket or retention mechanism. Whether true or not it's not a passive heatsink. The fan is just located in a different spot. Yes, but it goes to the point of stress against the socket, retention mechanism, or CPU during shipping... just another motivation for Dell to use this passive 'sink design. Doesn't need the same airflow over the CPU heatsink as the heatsink is operating with cooler case air, since it's not preheated with the exhaust from the CPU. Plus it's venting the case in addition to whatever case cooling you'd require when dumping CPU heat into the case. It doesn't need as much airflow given a 'sink of same efficiency, which is another issue that could expand this discussion into something more fit for a book rather than a newsgroup thread. Historically and today, passively cooled CPUs run hotter, even though they (all, AFAIK) use a duct. To many people this is considered common knowledge. Dumping CPU heat into the case with an active cooler isn't an issue of the significance that you suggest, since the airflow is moving in one direction, up and out of the case. Some heated air is mixed and recirculated though the heatsink but the airflow rate is SO much greater than even slightly warmer air results in a lower CPU temp. "Optimized" is precisely what an active HSF is not. On the contrary, it is optimized to cool the CPU, the exact goal. When a high quality sink is paired with a low-RPM fan, it is then futher optimized to have maximum cooling with minimum noise. It's the 'norm' for generic systems because one cannot make any assumptions about the system design: I.E. what else is in it and where anything is located. It has widespread adoption because it works well in comparision to the alternatives of similar cost. You can't count on there even being a rear exhaust port or, if it exists, that it's located where a 'standard' duct (that doesn't exist) would lead to, not to mention you don't know the exact location of the socket as that is left open, within reason, to the motherboard designer. Yes, the active 'sink works SO well that it can overcome all these obstacles most of the time. Not because it's "generic" but becuase it has such a huge margin over minimal efficiency required, that when a decent chassis is used the active sink works even better, even with a silent fan on it. But you CAN just slap an active HSF on it and then leave case cooling to someone else; with the typical solution being to slap gaggles of fans everywhere to 'cool' it. It's true enough that some people purchase, build, redesign, and outfit their systems in ignorance, but it has little to do with this topic since these same folks could either improve or degrade a ducted passive CPU cooling system using the same methods as on one actively cooled. We both know there are plenty of crap cases out there too, but that's not an argument towards a ducted cooling system, but rather to choose the case carefully regardless of which cooling system will be used. It's usually the situation that user mods to a passively cooled system have a greater impact, positive or negative, depending on where the fan is located and whether it's intake or exhaust. I suppose we just won't come to an agreement... it happens. I do despise long threads so if you want a thread where we can all argue about passive/ducted vs active cooling instead of hijacking Peter's thread, that's fine, but I'm done with this thread. Dave |
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"drumguy1384" wrote in message ... "127.0.0.1" wrote in message link.net... stay on topic please. Original Poster (OP) needs help with his overheating problem, not a debate on how well dell designs their mass produced products. Drumguy still has yet to post a solution. i gave my suggestion on adding a new Heat Sink (HS) + fan. what has Drumguy suggest? leave it alone because it shouldn't be overheating? that's not a solution. i'm not the type to lecture someone who needs help. if i can fix it, then i will. will i teach that person the physics involved in locating the cause of the problem? not for free. i may be ignorant, but at least i'm polite. my last post on this thread... Hey man, don't get me wrong. I'm not saying that a new cooling solution isn't what he needs ... but you said that the duct system is inferior in design to a conventional HS/Fan solution. I was merely disagreeing with you. I was not attempting to solve the OTP's problem ... only to take issue with your insinuations about the effectiveness of a duct cooler. But, since you insinuate that because I didn't tell him what I would do that I don't have a solution I'll get to it shortly. Shall I quote you? "thats a poor design." i guess that wasn't my last post... i still hold to my statement. i was being brief and to the point. dell's models aren't designed individually. err, i should go even further and say that dell doesn't design computer systems at all. they purchase existing systems that will make them money. i will stop here about poor designs. "having no fan on a cpu HS is not a good design. i'd rather see the dell executives cut their bonuses to save on cost than skimping out on proper cpu cooling." That's pretty inflammatory language there ... and hardly polite. if i wasn't polite... I was simply pointing out that you are wrong to say that a duct cooling system is worse than a traditional HS/Fan solution. not completely inflammatory. i was laid off in product development at lucent bell labs, thanks to the executive's cost cutting strategies. if i still had access, i can show you thermal data on that dell design compared to mac's. but with no data at hand, i'm just going to offer the client a simple solution. put a fan on the cpu. Sure, there are many aftermarket coolers that will do a better job of cooling his CPU ... but unless you find one with a 120mm fan (as his duct fan is) anything he get's will be louder. Of course I agree that a bit louder and stable is better than quiet and unstable. client didn't mention noise being a problem. But his heat problem may be easily curable by blowing any dust out of the heatsink fins and/or re-applying it using some high quality thermal paste, such as Arctic Silver III. It may also be that the fan in his duct system is crapping out ... which can and does happen, especially if it's left on all the time. In which case, if it can't be replaced independently of the duct, it'd be best to remove the duct system and use a conventional cooler and another quiet 120mm case fan in the back without the housing. However, if the fan is the culprit and it's not permanently affixed to the duct then the best course of action would be to replace it with another 120mm fan and leave the duct in place. if it was a $10,000.oo server, then yes, i would find out the cause of the overheating. but considering the clients level of expertise and the value of his pc, i would still recommend adding a fan on the HS. The truth is that this cooling solution works just fine in every system it's used in ... and it wouldn't continue to be used it if didn't work. Either it's crammed up with dust or the fan is crapping out. Simple as that. we aren't dealing with every system, this is a single client with a problem. a poor design doesn't mean it doesn't work. there are too many examples of poorly designed equipment to list that we use every day. the first design flaw, dust gets into the system. a good design will prevent any dust getting in. the next design flaw, heat generation. why even spend the money on removing massive heat from the case when there's good development that was canned which reduced processor heat. the intel processor itself is the main design flaw. i can go on forever about poor design that is acceptable. there's a difference between poor design and faulty design. Your first course of action was to can the whole cooling system and replace it with a louder conventional system ... because it was, in your opinion, "a poor design." I just submit that may not be necessary, and that he may do better to try and salvage what he's got. He would end up with an adequate cooling system that is as quiet as it's ever been, and keeps his CPU quite cool enough. your recommendation is to check the duct effeciency and checking the fan. with what test equipment? and what specs to compare it with? common sense dictates that dust should be blown off whenever seen. your final recommendation is what i stated earlier. put a fan on the HS. if that solves it, then testing the duct effeciency and fan resistance was a waste of time. not sure why you keep bringing up the fan noise as being a problem. the OP has no complaints about that matter. Good enough for ya? seems like you are more concerned about winning an arguement then helping out the OP. Drumguy |
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