Voltage Flucutation

I have a Asus P4P800 MB and I've been getting flucuations on the 3.3V indicator (asus probe). The flucuations range from as high as 3.7v and as low as 2.8v. It starts to occur right after playing about 1 hour or more of a graphic intensive program and is resolved by shutting down and restarting.

I changed the ac unit once and the mb twice but problem persists. The only thing that I can think that's to blame is the video card but can it cause these flucuations? The video card is a nvida ti4400 and the fan is working. The CPU and MB temps are normal as well.

Any suggestions?

[Jason425]

prob the PSU.. it's overheating and/or can't handle the load you're giving it..

Excuse my ignorance but what is a psu?

[Jason425]

the power supply

The power supply was replaced 350W to new 400W unit. The motherboard was also replaced twice.

[Jason425]

it COULD still be the psu.. what haven't you replaced?

The video card

[Jason425]

try a friends card

I tried another card and the fluctuations persists. I'm going to try running the motherboard outside of the case and with the bare essentials in terms of hardware (video card, hard drive, memory and PSU) to see if the same occurs ..maybe its a short in the case. If the problem persists, its safe to assume that the culprit is the PSU ...what would you recommend as a good psu?

[Jason425]

the antec trupower series is well known as a good pick...

enermax also makes decent, quiet psu's..

pc power and cooling make the best, but they're the most expensive. generally, you get what you pay for.