Some answers (yah, right)

Took some time during lunch to call up BFG and talk to technical support about my computer lockup issue. The person I talked to listened and agreed when I suggested that both power supplies I have tried are good enough to support the card (7800GS). So the next thing to try would be to swap in a similar video card and to try this video card in a similar system. These things are not really possible (I try to have one copy of each generation of computer hardware, not more), so I asked him to speculate. He pointed out that the different answers would be the video card or the motherboard are the root causes.

At this point, I recalled the trouble I had with my ATX power connector when I first got the motherboard. I had trouble inserting the connector - I don't know if it was the motherboard or the connector itself, but something was causing issues. These problems were both mechanical and electrical - it was hard to plug in and sometimes no power flowed. So I think that is the answer. This is not really the answer I wanted as it means spending more money.

The first thing I thought to try is to see if I can find a replacement socket 939 motherboard with AGP. Such a beast does not really exist in the one place I checked (ncix.com), but it is possible that some place may have a new-but-old board in stock. And I'd be happy to relieve them of it. Otherwise, it means starting over.

Now, that is not necessarily a bad thing - it's been about 3 years and I could do with some minor upgrades. This is a good time to buy - Intel and AMD are in the midst of a price war, so good CPUs are plentiful. Ram is at a reasonable price and all the other parts except power supplies and video cards are nice and cheap. But because I don't have the funds at this time, I can't really go out and drop a bundle on that. Nothing is stopping me from speculating however...

I'd get either an Athlon 64 X2 6000+ (~$240) or an Intel Core 2 Q6600 (~$340). 2GB of RAM is about $120, a good case ~$150, a DVD burner ~$45, a decent HDD ~$120. Biased by these power issues, I'd get the power supply I have wanted for a long time, a PC Power & Cooling. This company was recommended by Jerry Pournelle for many years in Byte magazine. Every current review speaks very highly of their quality parts and design - always the most efficient, stable and very quiet. They were recently bought by OCZ, which basically means that they know are available where I can buy them. So I'd be wanting a beefy PC Power & Cooling Silencer 750. That's about $230, twice a "good" power supply and 2/3 more than an "ok" power supply. Finally, the tradeoff would be on the video card. A decent card can be had for ~$180, but you can spend $250, $400 or $800. If I had to do it right now, i'd get the $180 card because I don't have a spectacular monitor - anything modern will drive it well.

Anyway, for now I have to try and keep the video card underclocked - that seems to help prevent most of the power-related lockups. Not the best thing, but at least there is a workaround. The system is very responsive and stable otherwise, so I think this is a good compromise. I have to find a way to make the settings stick though.