Folding Forum

300W alone isn't telling us much. We'd need to know if it has separate +12V rails for the CPU and the rest of the stuff. If so, how much juice do you have on the "rest of the stuff" +12V rail?

Asus GTX650-E-1GD5, for example, seems like a safe bet for just about anyone who has a free PCIE slot:
"Power Consumption up to 75Wno additional PCIe power required". Don't bother to overclock/overvolt that one, though. PCIE slot can supply max 75W, and that particular card already needs all of it at stock (1071MHz).

Older variants of 650 used to need an external 6pin PCIE power connector (max power consumption 64W at stock 1058MHz) - see http://www.geforce.com/hardware/desktop ... ifications - but then there's room for overclocking/overvolting if your PSU can handle that. If you GPU doesn't have a 6pin PCIE connector, there are Molex -> PCIE adapters available. In fact, you're likely to get such an adapter along with an older 650 by default.

The problem with recommending a video cards based on older PS's like that is that specifications have changed over the years. Modern PS give the vast majority of their power in the 12V line (used by video cards) but earlier PS didn't. Rather they would give a substantial amount of the spec'ed power to the 5v and 3.3v lines and the 12v power spec. would languish.

My point is that it is really very difficult to recommend a video card that would work well just by knowing the total power of the PS in an old PS for we need to know the 12V power capability. In general, I would say that it will not be enough for any video card using a 6-pin PCI-e power plug which is likely to need at least 75W unused on the 12V line; 150W for an 8-pin PCI-e power plug and 225W free for both a 6 and 8 pin plugs.

Sorry about the lack of information. I'll be honest, most of this is greek to me so I'm just glad that someone takes the time to explain things. I'm just trying to help as much as I can with the project.

Does this help any at all...?

Personally, I wouldn't use that PSU since it isn't a branded PSU. IMO, since a folding GPU runs 24/7, a branded PSU (Zalmam, Seasonic, Thermaltake, etc) of high efficiency is the way to go in the long run.

12v *15A = 180watts That's a little tight. The P4, when folding, would use about 80watts, leaving only a 100w for the GPU and anything else on the 12v rail.

If you happen to have a 115W P4 (source: http://ark.intel.com/products/family/58 ... or/desktop), you don't even have enough headroom to feed a GTX 650 without any external PCIE connectors: 115W + 75W == 190W. I'd recommend retiring that PSU for good, it simply isn't designed for modern 12V intensive loads.

EDIT: I have a 300W Bestec ATX-300-12Z rev:BC in my junk pile. It doesn't have any PCIE power connectors, which already tells you something, even though the design is a bit more modern: 12V * 19A == 228W.

He mentioned the 2.8 GHz chip earlier. So from your link...

Intel® Pentium® 4 Processor supporting HT Technology 2.80 GHz, 512K Cache, 800 MHz FSB Launched 69.7 W
Intel® Pentium® 4 Processor supporting HT Technology 2.80E GHz, 1M Cache, 800 MHz FSB EOIS Q1'04 89.0 W

I'd actually replace the PS too it is just too iffy. If you replace it, you can effectively buy any video card you want and match the PS to its needs.