Can not get modern games working with my machine FRUSTRATED PLEASE HELP

This is my first post on this forum and I really hope that it can help me understand and get my new machine working with games such as Fallout 3, F.E.A.R 2, Age of Empires III, Perimeter 2, and Wolfenstein.

To start I bought my desktop machine very recently. Specs: Q8200 Quad Core, 8GB DDR3 Ram, 1 TB HD, ATI Radeon HD 4650 and I am booting a dual monitor system (2x 24 inch LG monitors).

So, these games when played will work perfectly for about 5 minutes and then there are beginnings of sound stutter and then video and sound stutter eventually rendering the game useless to play. After I quit the game, my entire desktop is slow and lagging (eg. selection tool on desktop lags as well as mouse movements). This lag dissappears after about 10 minutes (or doing a full restart). I have looked at many different forums about this and I have done the following (for others that may be having the same problems)

1. Updated directX (there is a forum post about this already)
2. Ran in compatability mode
3. Re-imaged drive
4. installed vista codecs
5. Update to SP1 (came installed for me)
6. Updated BIOS
7. Re-installed/updated video driver
8. Turned down graphics on games
9. Disabled HD Audio (re-enabled because it did not help my problem)
10. Installed and used ATI Catalyst Suite

Please advise on anything that I might be missing!!!

Hi smallandlovable and welcome to Vista Forums

Have you checked the game manufacturers websites for any patches that are applicable for the games? Check the game forums as well to see if anyone else has had any similar issues and what they did to resolve them.

Hello smallandlovable,
I've somewhat had the same problem several times, but i have fixed it and im going fine now...now try looking at these things:
My first problem was that i overclocked my GPU and changed settings to max.this caused it to slow the games and suddenly hang the computer.
Second : Your CPU and other parts may be getting very hot, check your temperatures.
You can check your temperatures by HWmonitor.

I agree with amigo max. Your CPU might be overheating then throttling back. As it cools down it will re-adjust the clock speeds.

Download CoreTemp or RealTemp to monitor your CPU temperature.

The same for your GPU, although I don't believe an overheating GPU will cause your normal desktop to lag.

Try RivaTuner to monitor GPU temps.

Make sure nothing is overclocked and try to end as many processes as possible before starting a game.

Thanks a lot guys. This is very imformative. I did go to the ATI website and found brand new drivers (version 9.9) that I downloaded and my desktop seems to be likeing them and working with me FINALLY!!!! (Knock on wood). I will download some temperature monitors but i have a gigantic fan built in and it rarely goes on while gaming.

I will return if and when I run into more problems!

So I was running my game (AOE III) and it runs for about 30min now and then begines to stutter and lag. Same basic problems as before. I downloaded CoreTemp and RivaTuner and monitored it as I was playing my game.
Core temp: 47 - 57 for all cores
Fan speed: 25%
GPU usage: 80% max