System locking up in 3D Apps...

Hello,
I am running the system listed below. I am an active gamer and i cant game! its like a soldier with no ammo. I started with vista ultimate x64 and couldnt play any 3d applications (i.e COD4-MW, WoW, BF2, BF2142, UT, Guild Wars, Etc...) for more than 2 minutes tops before the system would lock up solid... no ctrl-alt-del, no alt-tab, nothing. i also get a sound loop/lock. have to reboot via power switch. read up online about it and noticed i was not alone. lots of users with my similar setup where having the same problem. most of which claimed it was a vista x64 os problem, so i downgraded to XP Pro x64 also figuring it was a driver conflict and much to my dismay i am having the same problems. ive tried everything to get this working correctly. flashed bios, just about every driver combo i could, flashing the GPU's. etc.. my system has sufficient cooling(4x 120mm and 1x90 case fans, 110mm on the cpu plus 110 on PSU.)
anything having similar concerns or have ran into this in the past and beat it? Any suggestions would help not matter how simple...sometimes a simple comment sparks a great idea.

thanks again

Cracktout




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3/20/08 Award BIOS
* Processor - Intel X3360 Yorkfield 2.83GHz QUAD
* Motherboard - DFI LANPARTY DK X48-T2RS
* RAM - Kingston HyperX 8GB DDR2 800 (4 x 2GB)
* PSU - 1000W X3 * HD - 2 x Western Digital Raptor X 150GB 10000 RPM (RAID 0)
* Sound Card - Creative Sound Blaster X-Fi Elite Pro 7.1 Channels 24-bit 192KHz
* Graphics Cards - 2 x VisionTek Radeon HD 3870 X2 1GB 512-bit GDDR3 PCI Express 2.0 x16 (CrossFire Enabled)
* Physics Card - ASUS PhysX Processing Unit 128MB 128-bit GDDR3
* OS - XP Pro x64