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Power Supply
I know this is a motherboard forum but im guessing you all would know if
your here anyway. Is there an easy way to tell what watt power supply i should get? or any site you could direct me to, Thanks |
#2
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Just get a good quality power supply at 300 Watts if you have a basic
system. Your motherboard and Chip take most of the power... lets say 90 watts together. A hard drive takes maybe 10 watts at most... same with the CDROM drive. So if the power supply is good quality and can handle it's rated current under load... should be no problem with just 300 Watts... maybe... the Zalman 300 watt puppy... inexpensive too. Jeff "TboXx" wrote in message m... I know this is a motherboard forum but im guessing you all would know if your here anyway. Is there an easy way to tell what watt power supply i should get? or any site you could direct me to, Thanks |
#3
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Are you in the uk? if so look here http://www.kustompcs.co.uk/
doughnut "TboXx" wrote in message m... I know this is a motherboard forum but im guessing you all would know if your here anyway. Is there an easy way to tell what watt power supply i should get? or any site you could direct me to, Thanks |
#4
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Actually U.S.
"Doughnut" wrote in message ... Are you in the uk? if so look here http://www.kustompcs.co.uk/ doughnut "TboXx" wrote in message m... I know this is a motherboard forum but im guessing you all would know if your here anyway. Is there an easy way to tell what watt power supply i should get? or any site you could direct me to, Thanks |
#5
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Try looking at:
alt.comp.hardware.homebuilt On Fri, 13 Feb 2004 21:01:29 UTC, "TboXx" wrote: I know this is a motherboard forum but im guessing you all would know if your here anyway. Is there an easy way to tell what watt power supply i should get? or any site you could direct me to, Thanks -- Fred Blau (Change "s@" to "systematics@") |
#6
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In article , "TboXx"
wrote: I know this is a motherboard forum but im guessing you all would know if your here anyway. Is there an easy way to tell what watt power supply i should get? or any site you could direct me to, Thanks A modern motherboard will have an ATX power connector and a 2x2 12V power connector for the processor. So, you need an ATX power supply to power it. At a minimum, those two connectors have to be connected to the motherboard, to make it go. The 2x2 (i.e. four pin) connector is used exclusively by the processor, and there is a conversion circuit on the motherboard, that converts the +12V from the ATX power supply, into the 1.500V or so, that a processor might need. The ATX power supply has six outputs. The consumption from the -5V and =12V outputs is so low, that there is no need to gauge the consumption. The +5VSB output on the supply is used for "keep alive" power. That power is used to save the contents of the DRAM chips, while the computer sleeps. It powers the LAN chip, in case a wake up packet is sent to the computer. It can be used to keep USB and PS/2 keyboards and mice powered, so they can be used to wake a sleeping computer. If you download the manual for the motherboard you plan on buying, there will be some estimates in there as to how much power might be required. These aays, many supplies have 1.5 or 2A for this function, and you can control some of the load on this supply, by changing the USBPWRxx or PS2 PWR header jumpers. The +3.3V and +5V outputs on most supplies will be in the 20A or so range. There is generally not enough information on power consumption of the various parts of the computer, to say how much is enough. But I can tell you by the process of deduction, that the consumption won't be too high. At one time, the processor derived its power, by converting the +5V output to the lower voltage needed by the processor. With the increased power consumption of processors, this function has been moved to +12V, and that is why, if you try to reuse an old ATX power supply, chances are the output on +12V will be insufficient for a new motherboard and processor. To work out the numbers for +12V, seeing as it is critical, I use Processor P4 3.2Ghz/FSB800/512KB cache = = 8.4A@12V Athlon 3200+/FSB400/512KB = = 6.4A@12V including 80% conversion efficiency, the required current is 10.5A or 8A for a top end P4 or Athlon respectively. Hard drive 2A during spinup of the disk, 0.5A while sitting in Windows desktop. Allow 0.5A for a CD. If you don't have a lot of drives, don't worry about spinup current, and concentrate on idle current. Fans Allow 1 amp for case and CPU fans. Video card Low end video cards use no +12V. An Nvidia FX5900 or an ATI9800 have a separate +12V cable, and as the video cards draw up to 70W when gaming, a maximum of 6 amps would be required. Unless you are buying one of these, a lesser number is more appropriate. Total = 15A for a basic system, with some margin. If buying a video card that requires extensive cooling, this number is more like 20A. Now, a reality check. The last computer I measured (2.6GHz/800 P4 865GE Northbridge) needed a total of 55W while idling in the Windows desktop, and 120W while gaming (wall power). So, you can see that the calculation above is quite pessimistic. That system didn't have a video card, as it used the builtin graphics, so consumption could rise by another 70W, if the system had a decent gaming video card in it. Here are some sample products. The first table is for some PCpowerandcooling.com products, considered the cadillac of power supplies. For my purposes, the 350ATX meets the minimum +12V current I would be after, so that is the smallest supply I would buy. You'll notice that the bigger supplies mostly increase the capacity of the rails you don't care about, so the 425ATX I would purchase to run a FX5900 or ATI9800 has got a lot more +3.3V than I would ever need. VOLTAGE --- +5V +12V +3.3V -5V -12V +5VSB Turbocool 300ATX PFC 30A 12A 14A 0.3A 1A 2A +5 & +3.3150W Turbocool 300 Dell 30A 12A 14A 0.3A 1A 2A +5 & +3.3150W Turbocool 350ATX 32A 15A 28A 0.3A 0.8A 2A +5 & +3.3215W Turbocool 425ATX 40A 20A 40A 0.3A 1A 2A +5 & +3.3300W Turbocool 510ATX 40A 34A 30A 0.3A 2A 3A total510W Here are the Antec Truepower series (antec-inc.com) - one step below a cadillac. VOLTAGE +5V +12V +3.3V -5V -12V +5VSB TRUE330 30A 17A 28A 0.5A 1.0A 2.0A TRUE380 35A 18A 28A 0.5A 1.0A 2.0A TRUE430 36A 20A 28A 0.5A 1.0A 2.0A TRUE480 38A 22A 30A 1.5A 1.0A 2.0A TRUE550 40A 24A 32A 0.5A 1.0A 2.0A Here, even the True330 is enough for a basic system, and the True430 is enough for a FX5900/ATI9800 gamer system. Use a similar comparison with bargain supplies. Gauge them by output currents and not total power. HTH, Paul |
#7
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Basically correct. However, the more you add, the more power you need. Buy
a good quality (name brand) PSU with a little more power then you need now, so you won't be in a jam if/when you upgrade or add-on down the road. For example, I started with two 7,200 rpm HDDs, but now have five 7,200 rpm HDDs, a Zip Drive (ATAPI), etc....all on my original Antec 330W PSU. ***** Also note the PSU's output on each voltage rail! Some claim high total power, but skimp on the 12V rails. So you can see, even two 300W+ PSU's can provide different "quality" of power output. ***** You can sum up the total power for each device, by voltage rating, then use the total power for each voltage rail as a MINIMUM guideline. I'd personally take AT-LEAST 25% more then the total usage figures as the minimum acceptable PSU rating for each voltage rail. You don't want a sub-par PSU as you might experience some strange errors that are extremely hard to track down or fix. The simplest two things to be certain of: 1) Name brand quality unit 2) 300W MINIMUM for modern average machine, much more for server type of setup and/or newer AGP graphics cards. "Jeff" wrote in message news:R0bXb.489067$X%5.330841@pd7tw2no... Just get a good quality power supply at 300 Watts if you have a basic system. Your motherboard and Chip take most of the power... lets say 90 watts together. A hard drive takes maybe 10 watts at most... same with the CDROM drive. So if the power supply is good quality and can handle it's rated current under load... should be no problem with just 300 Watts... maybe... the Zalman 300 watt puppy... inexpensive too. Jeff "TboXx" wrote in message m... I know this is a motherboard forum but im guessing you all would know if your here anyway. Is there an easy way to tell what watt power supply i should get? or any site you could direct me to, Thanks |
#8
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#9
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Paul beat-me-to-it with his excellent post later in this thread. Excellent,
and quite detailed, advice can be found in his reply. "KJ" wrote in message ... Basically correct. However, the more you add, the more power you need. Buy a good quality (name brand) PSU with a little more power then you need now, so you won't be in a jam if/when you upgrade or add-on down the road. For example, I started with two 7,200 rpm HDDs, but now have five 7,200 rpm HDDs, a Zip Drive (ATAPI), etc....all on my original Antec 330W PSU. ***** Also note the PSU's output on each voltage rail! Some claim high total power, but skimp on the 12V rails. So you can see, even two 300W+ PSU's can provide different "quality" of power output. ***** You can sum up the total power for each device, by voltage rating, then use the total power for each voltage rail as a MINIMUM guideline. I'd personally take AT-LEAST 25% more then the total usage figures as the minimum acceptable PSU rating for each voltage rail. You don't want a sub-par PSU as you might experience some strange errors that are extremely hard to track down or fix. The simplest two things to be certain of: 1) Name brand quality unit 2) 300W MINIMUM for modern average machine, much more for server type of setup and/or newer AGP graphics cards. "Jeff" wrote in message news:R0bXb.489067$X%5.330841@pd7tw2no... Just get a good quality power supply at 300 Watts if you have a basic system. Your motherboard and Chip take most of the power... lets say 90 watts together. A hard drive takes maybe 10 watts at most... same with the CDROM drive. So if the power supply is good quality and can handle it's rated current under load... should be no problem with just 300 Watts... maybe... the Zalman 300 watt puppy... inexpensive too. Jeff "TboXx" wrote in message m... I know this is a motherboard forum but im guessing you all would know if your here anyway. Is there an easy way to tell what watt power supply i should get? or any site you could direct me to, Thanks |
#10
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"TboXx" wrote in message
m... I know this is a motherboard forum but im guessing you all would know if your here anyway. Is there an easy way to tell what watt power supply i should get? or any site you could direct me to, Thanks Any good brand 300-400 watt should be fine. A good brand 250 watt will perform better than a generic 400 watt, so obviously the most important thing is to get a reputable brand (AOpen, Antec etc.). |
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