This is a micro-atx machine, so my choices for what PS would fit were limited. I figured 500w (2-16a 12v rails) would be enough to power it, but maybe I'm wrong.
At random points during game play the system will lock, blue screen and reboot. It's random and it doesn't seem to matter what game I'm playing. The only 2 I've tested so far are Civilization IV and Neverwinter Nights II, and both will crash. Strangely enough the system will run 3dmark06 without incident.
I've checked temp levels and the 7900gs doesn't get higher than 72°c or so, and the processor stays around 40°c during game play. Voltages on the 12v rail stay around 11.7, and will dip occasionally to 11.6.
The memory checks out fine on memtest86, and this is a fresh install of windows so I don't think it's a driver problem. I'd test with my old PS but it's a 300w and I don't know if it could power the system with the 7900gs. It only has 15a on the 12v rail.
What should I test next? I don't have another 7900 or anything close to test with, I was using onboard video. Should I just try the old PS and pray that it is enough to power it? Is there any way to see how many amps my system is pulling?
2 16a rails I thought would be enough for what I'm running. The Coolermaster doesn't list the wattage on the 12v rails though, so maybe it's way over rated.
I did try removing the Nvidia drivers running drive cleaner and then installing the drivers from the CD that shipped. Forceware 91.47 is what it ships with. I played an extended session (6 hours) of Civ with no issues. Weird that downgrading drivers would fix it, but we'll see in the next few days.
I was under the impression that the 7900gs only pulled 5amps or so. Anyway, I was really limited with what PS I could fit into the m-atx case, and even this one is a tight fit. Anything longer that the standard 140mm deep won't fit.
Thanks for the help, I'm really crossing my fingers that it was just a driver issue. If not then a larger case is in order.
While I value your contribution to THG Forumz, I'm going to have to disagree with you on the power supply issue. In my estimates, his system would be lucky to reach 170 watts of power under gaming situations. Even if all this power was from the 12 volt line, that's still only ~14 amps. Xbit labs measures the power consumption of the 7900 GS as 45 watts, although their test unit probably isn't the factory overclocked XFX:
Nvidia GPUs tend to source all their power through the 12V rail, and since CPUs also get there power from the 12V rail, the question of adequate amperes comes into play. The PSU in question supplies 16A per 12v rail. Although there could be a small chance that all the 12V power was supplied by only 1 line, I'd bet there was probably a bit more equal distribution between the two.
I agree w/ the consensus that the PSU is well within operating limits of the system in question.
Let's assume the worst case, and the CM marketing machine is at work, and the unit is a seventeam 450w - even if aging is an issue the unit should put out +12v@24A without any problem under typical loading. I do not think quality is an issue here, at the worst case it is slightly overstated on the label.
Look at Mrs B's unit, the eXtremePower600W - it is not a low quality unit by far it is an excellent 500w unit. It simply could not live up to the 600w combined output...
jonnyguru"]I was expecting something around the neighborhood of 570W. Unfortunately, the 12V rail crashed so hard that with this load I was only getting 536W. This is because the 12V rails dropped like the panties on a $2 whore. If this power supply was hooked up to a PC and not an ATE, it would have locked up like the chastity belt on a baptist minister's daughter. In other words: It failed to produce more power than what Seventeam claimed it could do as a 500W unit.
I recall getting a couple for $100 w/ $60 MIR, they were awesome deals a couple of years back.