Display Drivers stop working

I'm pretty sure many of us have been having this issue. Basically Whenever play a very high performance game (Crysis 2, Shogun 2, Call of Duty MW etc...) not even a few minutes into the game it will freeze up for about 30- 45 secs then resume. After hitting ALT-Tab their is a error that says "ATI DRIVER STOPPED WORKING AND WERE RECOVERED" It's becoming very annoying and really makes me feel as if all the money and time I have spent on my new rig is crap. I will leave my system specs and if someone could guide in the right direction on what to troubleshoot I'd appreicate it.

MB= Asus M4A89TD PRO
CPU= AMD Phenom X6 1090T 3.2GHZ
CPU Cooler= Ultra ChillTec Black Overclocking CPU Cooler
GPU= MSI Twin Froz II Radeon 6870 1GB
HDD= Western Digital Caviar 1 TB
DVD= Pioneer DVD ROM Drive
Chasis= Thermaltake Speedo Advance edition
PSU= Ultra 750 WATT Modular
RAM= Corsair XMS3 DDR3 1333MHZ (16GB TOTAL)
OS= Windows 7 Ultimate x64 with SP1 = Brand new install 2 weeks in operation.

PS: All system tempeatures are all well below normal levels (since I have 9 fans on the chasis)

Please let me know what I need to adjust or change.

Thank you all very much