Power supply.

If you're buying a high-end card, you'll need either a PSU with spare (2+) 6-pin PCI-E connectors and an 8-pin adaptor, or a PSU that has an 8-pin connector by default.

You're also probably going to want one in the 600-700W+ range, with better than 30A on the 12V rail.  40A is even better, but without more information it'd be somewhat difficult to suggest.  The primary deciding factor here is going to be what video card you want to run on it, while the secondary consideration is obviously going to be price, all other things being equal.

I've seen a lot of rigs using two cards in tandem. (linked together)  Is this something to consider? What's the benefit?

*Not to hijack the thread...just thought it may help.*

Check out the chart on this link: Toms Hardware Graphics Card Heirarchy Chart

and the accompanying article, there are also benchmarks on the same site that are quite helpful.

When it comes to dual-cards you have these options:

• top end cards from ATI and NVIDIA that are actually two cards sandwiched together and plug into a single PCI-E slot (but are probably double width)
• same cards but as separate cards each taking a single PCI-E slot but being (just) single width.
  
• one card

As stated above dual-cards are really only if you want to throw money at the problem - and also bear in mind that you don't need to buy them both at the same time (for separate cards) - you could add a second later.  Performance of two isn't 2x performance of one - it varies between zero performance boost and, if you are very lucky, 90%.

Do check out physical dimensions of the cards too - quite a few people have bought top end cards only to find they don't fit in the case!  You might need to check inside your case for obstructions.

i have 2 gainward 8800 gtx`s and most times my performance drops with SLI switched on

seems to help a bit in video rendering though..not worth the expense in my opinion

a 600W PSU is MORE than enough for a monster GFX card like 280GTX, or even a 260GTX SLI, it depends on the connectors. No need to waste money on more W

6150LE is onboard video. What motherboard do you have? You need a PCI-E slot.

This is probably due to the fact that if you're running a 3.2GHZ P4 you probably don't have sufficient spare power in your system to actually power the 8800GT.  However offhand I'm not even positive your default PSU would have a PCI-E power connector, which I believe one 6-pin is necessary for the 8800GT, so I'm not sure how you pulled that off.  I suppose maybe it comes with a molex to PCI-E adaptor?

Unless it's a proprietary due to being prebuilt (which isn't always the case), he's got one.  Even in that case, he's -probably- got one.  The 6100/6150 boards are /fairly/ good about this.  Would be nice to know the motherboard model number, though.

Download CPU-Z and run it, Lost.  There's a tab that says Mainboard, and down near the bottom third of the window with that tab selected, it'll specify what your graphics interface is.  Alternatively, Manufacturer and Model from the Motherboard section will give us enough information to verify.

On second thought, get us the second portion of the information as well-and/or your box's model number, if you can still find it.  I'm leaning more and more towards it being a prebuilt, and if it's a Dell, this is bound to cause problems.  (This is not to say that other prebuilts don't have issues with upgrading/exchanging components, but Dells have personally given me the most headache.)

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His RAM is fine-4GB would be nice but 32-bit XP won't let him use it all, and 3GB is just...eh.  Then again, RAM's cheap, so whatever.

PSU and video card are definitely the primary concerns here.

Show me where I said otherwise.  I said 600-700W+, and went on to further emphasize 12V amps.  There's nothing wrong with getting a larger PSU than one's current needs for upgradability, either.

No.

DirectX has nothing to do with it.

Your comment that it runs awesome contradicts with your statement that you didn't notice a difference.  For games that aren't graphically demanding, even up to GCII in a number of instances, this would be the case, but for virtually any games that have been discussed in this thread, you would definitely notice that it was not quite as good as you thought it would be.

The simple fact of the matter is it is highly probable given what little information I have on your system specs that your power supply cannot simultaneously provide peak power to your CPU and graphics card in addition to everything else in your system.  This is not a problem of it not having access to sufficient power, for instance not being of sufficient wattage, but simply that it is unable to division the power appropriately for the machine in question.  In the case of virtually any modern PC, your CPU and GPU both run off of the 12V rail of the PSU, but older PSUs were designed with the CPU and GPU running off the 5.5V rail in mind, so there's too much (effectively unusable) power on the 5.5V rail and too little on the 12V rail.  I don't know offhand whether the 3.2 P4s were off of 5.5V or 12V, but I'd probably need a core name to narrow it down, as I believe it changed at some point.  I'm guessing running from 12V on a PSU designed for large 5.5V loads, though.

As you do appear to have enough power left over to boot without bluescreening, it shouldn't be much of an issue, but I would recommend avoiding games that are both GPU intensive and CPU intensive, as that could in a best case scenario cause you to bluescreen and in a worst case scenario cause your power supply to die, perhaps in a fiery fashion.

Keep in mind that these are generic concerns expressed because I do not have sufficient valid information on your system to appropriately comment.  If you did upgrade your power supply before installing your new video card, then it's unlikely you need to worry about any of the above.

Ah, okay.  I guess I read it too fast.

Yeah-it seems there's a chance in hell it may be a Northwood, but at that generational stage, it doesn't appear to make much difference.

Still wouldn't hurt to verify.  You wouldn't believe some of the crazy things I've seen people do.  On second thought, maybe you would. 

Watts mean nothing.  Really.  It's all about the amps.  Your description of the function of the adaptor is not bad for someone who doesn't know what it does, but it doesn't and can't do that.  All it can do is allow you to actually connect your video card to the power supply, which I would assume it does by converting either one molex or probably two molex into a PCI-E.  Molex are the four-pin white/yellowish ones, by the way.  It doesn't change how the power is processed, and in what ways that power can be distributed.

I mean no offense, and was truly trying to help. 

While a model number on either your power supply or your system itself would be helpful, I think it's safe to say you're in the clear.