particularly when the vendors themselves are so cavilier about providing any real information.

How true. I've been in touch with HP support for about three days now and the tech assigned to me insists that my computer's psu (rated at 300w) is more than enough to handle my nvidia 7600GT card. Nvidia recommends 350w. So as you pointed out, what is a consumer, especially one like myself with limited comp knowledge, supposed to do? Like you said, to run the amp draw tests is just insanely time consuming over something that should be a cut and dry issue. This is why I said that I will just shell out the extra hundred or so and have the peace of mind that everything is more than 'up to snuff'.
The sad thing is I just bought this computer in June... and already having to improve it is just a pain in the ass. Now I am not that naive and know all about the constant technology changes... but come on. I will never again buy a prebuilt system. EVER. I think I'm just going to start stashing cash now and in a year or two I should have enough to go to the Monroeville Expo Mart and put together a system of my own. Who knows... I think it would be fun.

Did you buy this system from HP as it is or did you add the 7600GT yourself?

I bought the system at Circuit City. It has integrated nvidia 6150LE video, which didn't do badly with GC2, but still had some issues on a gigantic galaxy, late game.
I bought the card around the beginning of December and installed it myself. I totally wiped out my drivers (the one that came with the card was about two versions behind the most recent)and did a clean install with the most current drivers, as per CariElf. Works great and so far I am happy with it, but there seems to be an issue regarding the fan. After installing the vid card, the fan will now run on what seems to be 'high' whenever I first turn my computer on. As I play, regardless of what game, the fan will occasionally go on and off. Now I assume this is normal, but sometimes it doesn't seem to make sense 'when' it is kicking on. I've monitored the temp a few times and never really saw it make any kind of jump that would indicate an overheating issue, but as I said, I don't know much about this stuff.
Monroeville Expo is a gigantic tech 'fair' that goes on here in Pittsburgh roughly three to six times a year. If you know what you're doing with regards to electronics, it is THE place to go for all audio/video needs as the price is about as low as you can go. The problem is, you better know what you're doing because there is really no one there who is going to take the time to give you advice. Their take on it is "you should know what you're doing if you are attempting to do that" motto. There is some tech support there from the vendors, but again, you better have all of your info/numbers/whatever before walking in and filling your cart. I believe I am almost at that point.

Thanks for the link Mumblefratz. Even though I have limited knowledge in this field, it seems that I should be fine with a 300w psu, but I will still upgrade. Once the bug is in me, it's all over. Besides, maybe I can throw in a little something on top of the 'wish list' without the wife protesting too much.
Incidentally, did you finally get to play GC2 on your new computer yet? If so, how did you like it? Originally I thought I saw you write that you were getting a 7900 card, so when I read that you have the 7600GT I was a little confused. It's the competition thing... no sooner I go out and buy a card and then you announce that you're getting a new computer... I just try to stay ahead of the game a little, that's all.
You've been a great help in a lot of ways Mumblefratz, and this is another fine example. I couldn't seem to find my card's specs (with regards to power usage)anywhere... and viola! Mumblefratz to the rescue.

Thank you for contacting NVIDIA Customer Care.

I understand that you would like to know the recommended power supply for the GeForce 7600 GT graphics card.

Mike, the recommended power supply for the GeForce 7600GT graphics card is 450Watts.

Regards,

NVIDIA Customer Care.

Just wanted to share this email with you Mumblefratz since I know you said that you have a 350w power supply. I asked this question and specified that I would only be running with one card, not a dual set-up. The recommended power is still 450w. Guess that goes to show what you commented on earlier...

input voltage for 300W models:

100-127v/6A
200-240V/3A

maximum output wattage - 300W or 250W


To know the specifications of Nvidia GeForce 7600 GT Graphics Card,
please visit the web link provided below. The power consumption for this
card is 67 W.

http://www.techarp.com/showarticle.aspx?artno=318

The one above and this one following were from HP
In checking the specifications of your PC, I found out that the Power
Supply installed on your PC is 300 W and it is sufficient to install a
Video Card.

If what you mean by what I commented on earlier is that these folks apparently can't tell the difference between their ass and a hole in the ground, then yes.

That is a big AFFIRMATIVE.

This whole debate gets really convoluted in a hurry. You can get to the bottom of it, but it takes a fair amount of time and a certain tolerance for ambiguity. I just got done doing a bunch of research on how to replace my 250W Dell PSU, after I wanted to upgrade my PSU, so here's what I learned...

If you want to estimate power consumption for a card, I'd just go to a good product site with lots of informed customer reviews (I found www.newegg.com to be the best site) and see what comments people might make about power requirements.

The reason NVidia, like all the game card manufacturers, err on the high side in terms of estimating wattage requirements is because power consumption is complicated, they don't trust vendors to publicize all the information that's needed, and they don't trust most customers to figure it out.

The main requirement for a driver is how many Amps you can run on your 12V rail. In general, bigger PSUs (with higher Wattage) have higher Amp limits on their 12V rail(s).

However, the video card isn't the only thing drawing on a PSU (the processor and various drives join the list of usual suspects here). If a PSU is generating too much power for too many different things, regardless of how much current a single rail can support, it'll start to heat up in a hurry.

If it runs too hot, and there's no good way dissipate that heat (that's why they talk about fans and cooling), bad things can happen to your computer. You can get a feel for some of these details at a site like http://www.pcpower.com/technology/myths/.

Happy Hunting!!   

Not to rain on your parade but besides a maximum current drawn from each different power rail, there's also a minimum current drawn requirement as well. This is due to issues of stability. You might want to verify that it's OK to draw no load on your two currently unused 12V rails.

[edit] It never seems to end, doesn't it? [/edit]