Further computation updates

As I mentioned here, I still haven't returned my OCZ ram to see if I can get it fixed. However, last Friday I did manage to send off my 2nd, not-properly-functioning BFG 6800GT. Today UPS showed up with the replacement. To my surprise and amazement, it was a BFG 7600 GS! Sweet! This card is a little newer and I was pretty sure that it used a little less power. Now that I have checked the specs more carefully, I think it withstands temperature better, is a smaller length, but has higher power requirements.

Specifically, when I compare the old power requirements with the new, the 6800GT requires a 300W power supply. I started off with a 430W power supply, but upgraded to an Antec TruePower 480 when I first put things together. Should be more than enough. The new card is more specific - 350W with a minimum 12V+ rating of 20 A. Those of you who keep with the vagaries of modern multi-video card systems will realize that this is pretty tamed compared to some Quad-SLI system and the 1100 and 1200W power supplies now available. When I was putting this machine together, the 6xxx series chips from NVidia represented the highest power consumption in video cards - the SLI and Crossfire technologies are only support on PCI-e. Such motherboards were available, but I went the AGP route, but I did buy a video card that required a lot of power. With an Antec 480 W supply, I thought I would be fine as Antec power supplies were part of a test group that reliably matched their number with their real output. What I didn't realize at the time, and has become more essential in the multi-GPU setups is the per-rail output ratings. The only option at the time was to go "bigger", but that just upped the rating for each rail.

So I checked the online ratings from Antec for this power supply. You can see in the "Output" chart that the 12V line had a max rating of 28A, easily handling the requirements. The sticker on my particular power supply notes that the max output is 20A, startlingly close to the minimum requirement for this power supply. Why bring all this up? the machine would do a hard lockup when I hit certain intense gaming situations. Knowing all this, you can understand why I decided to buy a new power supply.

Getting back to power supplies, the vendors have adapted to the higher requirements in multi-GPU systems by adding additional, independent 12V+ rails. This way the graphics card can be given its own rail with a 20A (or higher) rating. A quick check to trusty ncix.com showed that there are several suitable power supplies with multiple 12V rails available for ~ $100. The Antec NeoHE 500 power supply is a dual-standard EPS12V and ATX 2.0.1 power supply with 3 independent 12 V rails and an efficiency >= 85%.

As an interim solution, I've under-clocked the video card (using the CoolBits registry hack to unlock the NVidia driver). I believe that should keep it away from the brink. Probably this was what allowed my older 6800 GT to work reliably. But now I need to get something to ensure real reliability.