Why is a new PC failing?

[intex_X]

Hi, i have a problem with my PC i built a week ago. I installed Win7 Pro 64-bit and downloaded all the latest drivers for my motherboard and the graphics card, so i installed a couple of games like: BF:BC2, crysis, crysis 2 , dirt3, F1 2010...All the games work very very smooth im hitting 80FPS on crysis. But games like BF:BC2, dirt3, F1 2010 just simply freeze and nothing happens (i can leave it for 3 hours). So i have to restart my PC which happens 3-4 times a day and its really annoying. Now that's what i think is weird only BC2 dirt3 and F1 2010 freeze...i can play crysis1, 2 the whole day and it wont freeze. I get great performance in all of the games but after some time (15-60 minutes) the game freezes. First i thought my CPU or the graphics card is overheating...so i bought a new CPU cooler (my stock 2600K temps are ~52C 100% load) and a few case fans (4x120mm + 2x200mm) but the games were still freezing...i tried reinstalling all of these games but the same happens. My graphics card temp is 78-83C on 100% load.
Please answer so that we can find a solution together.

My specs are: ASUS P8P67 Pro Rev 3.1 motherboard, Intel core i7 2600K@3.4ghz, 8gb ddr3 Kingston HyperX 1600mhz ram, AMD Radeon HD6990, LC Power 80 Plus Gold 1000W PSU.

 

[mjw75]

Is your CPU overclocked? How close is your GPU to your CPU chip? I had a similar problem a couple of years ago...turns out the gpu was transferring heat to the cpu and the 100% loads weren't taking this into considertaion...the 6990 is also a VERY large gpu. If your tower allows it, try adding more space between the 2 components.

This is a tricky problem because it's not happening for Crysis 2 which'll (I think...depending on your in-game specs) require the most from your 6990. Also, who produced your 6990 (msi, xfx, asus, etc)?

 

[intex_X]

Club 3D Radeon HD6990

 

[intex_X]

Nothing in my pc overclocked...the cpu temperatures never go over 55C.