krillz:
Two questions:
You said your XFX8800GTS (640) has an 8 pin connector for PCI-e power. Are you sure it's not a 6 pin connector?
Second, when you said the PC "crashes", did you mean that it occasionally freezes or that it will randomly reboot? If the latter, it's probably power related - especially if it happens under heavy system load.
An OC'd G80 8800GTS/640 MB needs about 120 watts of power.
For PSU ratings, ignore any rating that says "peak power". It's meaningless. If you are operating that close to the upper edge of PSU capacity, you need a heavier PSU.
I went over to the Apevia website and looked at the pictures and specications. The pictures seem to show pretty light heatsinks. Specs say full rated output at 25 c. Under load, it will heat up. Based on data from PSU manufacturers who do publish such data (most don't), you need to derate a PSU from 1 to 2% per degree C. over PSU rated operating temp. So if internal temp goes up just 10 deg. C., this 500 watt PSU turns into a 400 to 450 watt PSU. This is far different from a 430 watt PSU rated at full output at 50 deg. C. My impression of Apevia is that you would have received a better PSU if they dispensed with the acrylic and LED fans and put that money into the electronics.
croc:
Your automotive analogy really isn't accurate. An inadequate power condition (an overloaded PSU) is supposed to shut that PSU down. A more accurate automotive analogy would be "running on empty". You may still have some gas in the bottom of the tank, but it's not enough to reliably feed the fuel system.
JAYDEEJOHN :
LOL 20 watts, not thatd be a miracle! I know my 420 watt psu can kick 29 amps to the 12s, and 25 seems weak for a 500 watter, to me.
New PC's really load the 12 volt outputs. So new PSU's are designed for that. Older PSU's were designed for older PC's that needed more 5 volt power. So 25 amps out of an older design is not unreasonable. Modern PC's do not need all that 5 volt capacity. But it's included because it might be a replacement PSU for an older computer.
nukemaster:
"They are combined rails(most likely center tapped from the same transformer) similar to the way you can get more 12 volts if you use less 3.3 and 5[they are clearly linked too]......"
That's sort of a simplification. The limitation is actually determined by the primary power circuits (how much power the switching transistors can provide and the size of the main power transformer) and the thermal characteristics (heatsinks, ventilation, and layout). "More power" costs. That combined with good design and conservative ratings is responsible for the difference a $20 no-name PSU from China and a $100 to $150 1st or 2nd tier PSU.
My Antec 650 watt TP3 box says "650 watt continuous output at 50 deg. C." It also say that the max 12 volt out is 624 watts, leaving 26 watts for everything else. <Snicker>
"Quick and dirty" under load PSU voltage checks (carefully, carefully) of the main outputs with DMM black lead grounded and red lead inserted into the back of the various PSU connector pins plugged into the motherboard:
yellow, yellow/black, and yellow/blue wires: +12 v
red: +5 volt
orange: +3.3 volts
All readings should be +- 5%.
While we are talking about PSU's, if you have a suspected bad PSU, also check the grey wire on pin 8. It provides a control signal called "PwrOK" that the CPU
needs to start booting. With the PC off, it should be at 0 volts. It should go to around 5 volts (anything over 3.6 volts will be OK) within .5 seconds after pressing the power switch. You can have all the power outputs present. But if you don't have this, your PSU is broke and your PC won't boot.
I also have been thinking about doing a basic PSU guide. I am getting tired of writing the same things over and over in PSU threads. Thats how my "Troubleshooting a Dead System" guide evolved.
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