Always pay attention to amps
, without it, wattage has no context. Some higher quality PSU's have more 12v amps than others with more wattage; so you can't just refer to a PSU or what a system needs by wattage alone.
This is why EVGA and NVIDIA recommend a 550W PSU at minimum.
pcmaster00, I don't know if you learned from me or not, you post was a good call, certainly much smaller.
Something to considering with either AMD or Intel or nVidia: TDP isn't electrical draw, it is just a category.
Even nVidia doesn't call the power draw of their cards TDP, they call it 'board power'. A central processor's real TDP could be anywhere from 95W to 125W (it could have a full load of 96W TDP), thus given the category name of 125W TDP. But it's electrical power draw is definitely higher than 125W (closer to 150W considering efficiency ratings), so the amp rating puts him in the danger zone with his PSU unless he's willing to reset to stock.
As for why EVGA and nVidia recommend more, I think it has to be with liability mainly. If they didn't include a recommendation for system power, people are free to get anything and ruin their graphics card if they get too little, all while expecting EVGA/nVidia to be responsible for RMA's-- which is a waste of their money due to customer negligence. Hence higher average system power recommendations.
Fact is, if someone used a fast dual-core with HT, like i5-655K or Core i3-2130, paired with a GTX690, and the basics, they wouldn't need a PSU with more than 32A from 12v, which is in the range of most 450-500W units -- but nVidia throws up a 700W requirement. It is more about liability, nVidia can't gaurantee what we put in our systems and how long we keep it, or even the quality of unit we buy, so a generalized PSU only makes sense if it is exaggerated.
<message edited by lehpron on Thursday, June 21, 2012 3:09 PM>