Sorry, that's a gross misconception about power supplies. That number is only good for a few months then is some many percent less a year later. I offered a recent explanation why recently, but lets jump to this article -> http://www.tomshardware.com/howto/20021021/index.html In this expose', 6 or more out of 21 supplies failed to meet their printed specs.
Users worldwide fall for the trap that "this power supply is big enough".
I am having some very puzzling problems with my DELL Dimension 4700 series computer. Here's the story:
I just installed a brand new ATi Radeon x700 PRO 256MB PCI express card in my computer and since then, if the computer has been of for more than 12 hours and I turn it on, all of the fans kick in full speed and don't stop(the fan on the x700 is quite loud in full speed), there is no picture (not even for a second), and the computer does not boot. I then hold the power button for 7 seconds, do a hard shutdown, and turn the computer on again. I go through this process sometimes 7 or 8 times before the computer boots properly (usually works the second or third), but when it does boot, the computer and the video card both work absolutely flawlessly. And if the computer has only been of for 6 hours or less, it boots up on the first try...
So theres my story. Both ATi and DELL tech support were no help at all, and when I emailed ATi to tell them they didn't help, they never responded. I checked the power consumption of my computer and it is well within the limits of my power supply, although it is only a 305W power supply. My buddies at gamingforums.com have been throwing this around for a week, and noone can come up with a working explanaiton. PLEASE HELP