Crashes under heavy loads, games and videos.

Hello,

Last year I had crashes during games and benchmarks of the GPU(Furmark).
After about half an hour of playing games the computer just restarted. It was a faulty PSU that I changed and all worked fine.

Two weeks ago the problems started again:
It started with the screen turning black(signal lose) during games for few seconds and the speakers making noise. It was only for few seconds, no restarts.
Then, the screen was turning off again with the noise from the speakers and the computer restarted, the GPU fans went max RPM and the Motherboard made 1 long and 3 short beeps. I had to turn off the PSU with the button to restart.

From what I read I could be a driver problem. I re installed Windows after formatting all the disks.
Now I test with Furmark on any resolution and the computer restarts after I start the benchmark.

Also, It crashed when I watched videos on YouTube, I understood it came from flash hardware acceleration.
The video Crashes stopped
I also Had a BSOD on Idle but then restarted..

What I found is when in Nvidia inspector I put the power and temperature target to minimum(67%) the crash was only after ~10 minutes of the benchmark and not immediately.

My Computer:
I7 2600K
Asus P8P67
Gainward GTX680 4GB
Corsair 1200W PSU
Corsair vengeance 4Gb stick x4

I'm running all on 2560x1440 display.

Thank you for help.

Thank you, I will test now.
As I said The store where i built the computer changed my old 750W PSU last year. I added to buy this because I was planning to add another card and screen this year..

Thank you for the fast replay.

Ok, I tested all the RAM sticks. Crashing on all.
Here is a small video of the crash with Inspector open: https://www.youtube.com/watch?v=MwYPtWdnqtk

With furmark it's crashing without the MoBo beeps..

Thank you.

I uploaded the zip file.
I don't know how can I connect the monitor to the motherboard, I don't find any place to connect something like a monitor cable. Again it's Asus P8P67.

Thank you.

It's just P8P67.
I also updated the BIOS but no change.

Thomas.