You are always an amazing font of information, Hegelian.
Either way, the machine has a COOLMAX "EZ Wire" CU-400T ATX 400W Power Supply. Here's the link to it on NewEgg:
http://www.newegg.com/product/product.aspx?Item=N82E16817159047. Most of the specs mean nothing to me. I was told it was a pretty good power supply, but I have no idea what that really means in terms of upgrading the video card.
If I were in your situation, I would start by upgrading the power supply. It really isn't adequate for modern motherboards, being designed for older—old even—motherboards with ISA slots. How do I know this? Well, let's look at the specs:
+3.3V@30A
+5V@40A
+12V@18A
-5V@1A
-12V@1A
+5VSB@2.5AWithout going into an excess of detail, let's just say that these voltages represent the power feeds to different components in your PC:
- The +12V "rail" powers newer CPUs, devices like hard drives that use the large four-pin Molex connectors, and PCI-E slots and connectors.
- The +5V rail powers the PCI slots, the floppy drive, and older CPUs like the PIII, and also contributes to devices that use those big Molex plugs.
- The +3.3V rail powers RAM, the AGP slot, and some motherboard components.
- The -5V rail powers ISA slots.
So what does this mean? Note the whopping 40 amps on the +5V rail. You have only three PCI slots and you may not even have a floppy drive; you certainly don't have a Pentium III CPU. Therefore, 40A is overkill.
On the other hand,
your +12V rail is powering your hard drives and optical drives, the CPU, and your PCI-E graphics board as well (and PCI-E boards draw considerably more wattage than do AGP boards), but can only offer up 18 amps (and note the efficiency of this unit is only about 65%, which is pretty poor). 18A for the +12V rail in this PC is woefully insufficient; you would like at least 30A, and doubling to 36A wouldn't be bad.
30 amps for the +3.3V rail is fine.
The -5V rail is useless, since that pin (18) on your motherboard is a ground line, not -5V, because there are no ISA slots on your motherboard.
This is a surprisingly expensive power supply considering its age and low efficiency; presumably what you're paying for are the modular cables, which, all else being equal, is not really a good idea because you lose some efficiency at the connections.
So what do you want? Your graphics board requires the 6-pin PCI-E power connection, so presumably it draws some significant power. You don't say what else you have in your PC but I'm guessing only one hard drive, one or two optical drives, and perhaps a modem, but no plug-in sound board or networking card. Even if you have a bit more than this, a quality unit in the 500W range should do the trick—I'm running three 10K rpm SCSI hard drives, two optical drives, a floppy drive, a modem, a sound card, a 2.8GHz Pentium IV, 2 GB RAM, an overclocked ATI X800GTO video board, and a bunch of case fans (and, until recently, a SCSI tape drive) with a 510W PSU from PC Power & Cooling with no problems whatsoever.
Something like this
SeaSonic SS-500ES ATX12V 2.2 / EPS12V 2.91 500W Power Supply would be a good choice, rated at >80% efficiency and with two 17A +12V rails (some would argue that single 34A rail would be better, but the latest ATX spec calls for two +12V rails, one for the motherboard and CPU and the other for peripherals). This is currently US$70 ($30 discount) with free shipping from Newegg. This is the same unit as the Antec Earthwatts EA500 for $10 less. Of course, if you're not in the US you'll need to find another supplier. Brands to look for are SeaSonic, some Antec (Earthwatts, for example), Corsair, Enermax, and PC Power & Cooling. There are a
lot of really crappy power supplies on the market, so beware!
Here are the specs for the SeaSonic (note the absence of a -5V rail):
+5V@24A
+3.3V@24A
+12V1@17A
+12V2@17A
-12V@.8A
+5VSB@2.5AIf a new PSU designed for your hardware doesn't fix the problem, you may then wish to consider changing the graphics board. Wasn't the 6800 series among the nVidia products that had so many driver problems when running TS2? You may want to do a search of this site to see what you can turn up, as there was quite a bit of discussion about this and which driver versions to use.