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#11
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Marc Brown wrote:
Subject says it all. I hadn't really planned on buying a new power supply (I currently own a 420W semi-generic), but when I think about the 6800 Ultra's original recommended wattage, plus the fact that I'll be trying to overclock the Ultra, ram and cpu, I begin to suspect that I may need something more. This may be incorrect. Feel free to enlighten. 6800 Ultra power usage report: http://www.xbitlabs.com/articles/vid...v-power_2.html Table of power usage at http://www.xbitlabs.com/images/video...0u_table-b.gif So right off the bat, it's going to be eating ~55W off the 12V line, and ~23W off the 5V line. Add in the CPU at 90W, thrown in the regulator efficiency at ~80% to get ~115W, and you're already up to at least 14A on the 12V and 5A on the 5V line. Hard drives, once spun up (they'll only spin up when your GPU isn't working), consume about 0.5A off the 12V and ~1A on the 5V. Add in the motherboard (southbridge and other chips have to be powered), case fans (small usage off the 12V, ~0.2A for a normal fan), usb devices, etc etc and you can easily get to 18A from the 12V under gaming conditions. So the minimum you should be looking for is 20A on the 12V, though I'd feel much safer with 23A or so. As long as the 5V line can supply 20A or so you should be fine, as not too much stuff uses 5V nowadays. [...] -- Michael Brown www.emboss.co.nz : OOS/RSI software and more Add michael@ to emboss.co.nz - My inbox is always open |
#12
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Thanks for those links. Does anyone know of a site showing similar power
consumption information for a GF4 Ti4600 at full load? I'm curious about how much more power the 6800GT draws compared to a GF4 Ti4600. Thanks, Larry "Michael Brown" wrote in message ... Marc Brown wrote: Subject says it all. I hadn't really planned on buying a new power supply (I currently own a 420W semi-generic), but when I think about the 6800 Ultra's original recommended wattage, plus the fact that I'll be trying to overclock the Ultra, ram and cpu, I begin to suspect that I may need something more. This may be incorrect. Feel free to enlighten. 6800 Ultra power usage report: http://www.xbitlabs.com/articles/vid...v-power_2.html Table of power usage at http://www.xbitlabs.com/images/video...0u_table-b.gif So right off the bat, it's going to be eating ~55W off the 12V line, and ~23W off the 5V line. Add in the CPU at 90W, thrown in the regulator efficiency at ~80% to get ~115W, and you're already up to at least 14A on the 12V and 5A on the 5V line. Hard drives, once spun up (they'll only spin up when your GPU isn't working), consume about 0.5A off the 12V and ~1A on the 5V. Add in the motherboard (southbridge and other chips have to be powered), case fans (small usage off the 12V, ~0.2A for a normal fan), usb devices, etc etc and you can easily get to 18A from the 12V under gaming conditions. So the minimum you should be looking for is 20A on the 12V, though I'd feel much safer with 23A or so. As long as the 5V line can supply 20A or so you should be fine, as not too much stuff uses 5V nowadays. [...] -- Michael Brown www.emboss.co.nz : OOS/RSI software and more Add michael@ to emboss.co.nz - My inbox is always open |
#13
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On Sat, 2 Oct 2004 00:13:17 -0700, "David Hughes"
wrote: http://forums.pcper.com/showthread.p...7&page=1&pp=15 There is one major problem with that thread, that they are making the age-old mistake of trusting Enermax's amperage ratings on the label. Enermax does not rate sustained amperage or wattage like the better power supplies do. Figure 70% of Enermax's rating to compare to some other well-known major brands. |
#14
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Aside from the issues of cheap power supplies putting out too little
power for the needed voltages or of putting out "dirty" power, many cheap power supplies tend to be quite noisy. It doesn't make sense to suffer with a noisy pc when for a relatively small additional amount, one can have a quiet one. http://www.quietpcusa.com/ Marc Brown wrote: Subject says it all. I hadn't really planned on buying a new power supply (I currently own a 420W semi-generic), but when I think about the 6800 Ultra's original recommended wattage, plus the fact that I'll be trying to overclock the Ultra, ram and cpu, I begin to suspect that I may need something more. This may be incorrect. Feel free to enlighten. Assuming I do need something more, what should I get? It looks like a regular, non-elite 480W can be had for $75 or less. Or for as much as $150. A lot of variety with power supplies, most of which I suspect is the manufacturers taking advantage of pricing ambiguity. I can, for example, understand why a 6800 Ultra costs 25% more than a 6800 GT, but the advantages provided by one power supply which costs 100% more than an alternative are totally unknown to me. I don't need the ultimate power supply.. that I know of, anyway. Who knows? Maybe it really is a good idea for some reason. Again, enlightenment would be appreciated. And would 480W be enough, or would there be a risk of me taxing even that? Thanks as always. |
#15
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In article ,
says... PSU is one of important component in a PC. Not everyone think of PSU when purchasing or place on top of the list. Yep, I used to buy the cheap PSUs and caused a bit of self-inflicted suffering (RAID sets that would mysteriously fail and have to resync, reboots and other strange behavior). Buy a good quality power-supply, and you'll still be using it 5 years from now. I think I usually pay about $80 for a good P/S (480W), which is a good bit cheaper then replacing failed components down the road. |
#16
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"Michael Brown" wrote in message ...
So the minimum you should be looking for is 20A on the 12V, though I'd feel much safer with 23A or so. As long as the 5V line can supply 20A or so you should be fine, as not too much stuff uses 5V nowadays. Thanks for the many helpful replies, folks. I settled upon the Antec True550. There seems to be a fair chance this will prove adequate. |
#17
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I'm not going to argue the advantages, if any, of an expensive PSU, but
hell would have to freeze over before I paid more than $25 for a PSU. I agree that most brand-name PSUs are overpriced, but having seen a cheap no-name PSU burn out, taking a motherboard, hard drive, and CD-ROM drive with it, I no longer trust my systems to $10 PSUs. At the very least, I'd make sure to get something with overvoltage protection. Also, read the fine print. One cheap "500W" power supply I bought computes its wattage rating by adding the total wattage for each rail, assuming that all the other rails are unloaded. This is a next to useless measure for a real PC. The actual maximum power rating for the unit is only 282W. |
#18
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On Sun, 03 Oct 2004 22:59:41 -0600, Lachoneus
wrote: I'm not going to argue the advantages, if any, of an expensive PSU, but hell would have to freeze over before I paid more than $25 for a PSU. I agree that most brand-name PSUs are overpriced, but having seen a cheap no-name PSU burn out, taking a motherboard, hard drive, and CD-ROM drive with it, I no longer trust my systems to $10 PSUs. At the very least, I'd make sure to get something with overvoltage protection. Also, read the fine print. One cheap "500W" power supply I bought computes its wattage rating by adding the total wattage for each rail, assuming that all the other rails are unloaded. This is a next to useless measure for a real PC. The actual maximum power rating for the unit is only 282W. You were lucky to find a label on it that honestly stated the true max rating... usually that is omitted. |
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