That would be too much of a hassle though. Are there any ways to check if there is a problem? Maybe a 3D mark test?

Nvidia has their own benchmarking/tuneup utility called ntune. Just go to their website and search for it and it will add the tests to the nvidia control panel under the performance tab.

Also, 3DMark05 v130 is freeware from3DMark05 v130 download from Guru3D.com. It says that only xp is supported, but I'm downloading it on my win7 computer right now to see if it works and I'll let you know.

You can also try sisoft sandra which has benchmarks for everything and it has a free trial up to 75 modules (you can use up to 75 different benchmark tests before you have to buy). You can get it here - SiSoftware Sandra - Free software downloads and software reviews - CNET Download.com. This one's my personal favorite, I've been using it for years.

3DMark05 installed and ran on Win7 but had problems with aero and some other problem that turned the screen black (didn't lock up and came out of it as soon as I hit ctl-alt-del), so I'm guessing it probably wont work well on your vista machine. You can try it though if you want.

Do you know if your friend has over clocked his card this could give him a higher FPS ..

One other bit of advice that I've given others recently with Nvidia card problems is if you're using drivers version 185.xx, 186.xx, or 190.xx, go here - NVIDIA Driver Downloads - Advanced Search and fill in all the info on which card you have, what widows version, etc. and look for the 182.50 drivers and download and install (after removing the old drivers through add/remove programs of course) those and see if you get any FPS increase. All of those other drivers had a lot of bugs in them although I never checked to see if FPS was one of them.

Nope, my friend doesn't have an overclocked card. My drivers are the latest, 190.xx, I think. Could it be the PSU like someone had suggested in a post earlier? Mine is 460W but the recommended is 500W on the 9600GT box. With 4GB RAM, it's unlikely RAM problems.

I would definitely try the 182.50 drivers first before thinking about the PSU. Those are easier and a lot cheaper to replace.