Monitor goes into sleeping mode during gameplay

[Andrei Bogorodski]

Hello everyone, so i have this issue started about 2 weeks ago, at first i only had the issue
with just about 2 games, but then with time i started to have it with more and more games,
up until today where i played a simple game called "Craft the World" and my pc crashed.
Basically what is happening is that during gameplay, at random times, suddenly the monitor goes into sleeping mode, while i hear the fans still running and the sound still playing.
If i click anything, the PC hangs, the only way out is hard reset.
At first i suspected it was my Hunkey PSU, so i bought a new PSU, my specs are:
Intel Core i5 3570 @ 3.40GHz
MB: ASUS P8Z77-M
2x4GB DDR3 Dual Channel @ 812.1 MHz G.Skill
ASUS 295 GTX
PSU: SeaSonic S12G-550 Gold Active PFC 12cm <--- brand new PSU
Win7 Ultimate 64Bit

After i installed the PSU i still had the same issue, so i reinstalled Windows, and it didnt helped.
I updated all my drivers, including BIOS, still had the same problem.
I tried older video drivers, still had the same problem :<
Now i suspect my GPU card is dieing, but how can i know for sure?
i just spent a good sum of money on a new PSU and it wasnt even the problem!
I ran OCCT test for 30 min and received no errors, so how come during game my PC fails?
I checked the temperature of my system including GPU, all was within normal range.
I even tried to switch connections from one DVI to another DVI output on my GPU
and obviously it didnt helped.
Another thing i noticed and only in one game, is that i had graphical artifacts, but it only happened once and i didnt encountered it ever again.

Edit: when i removing the GPU and plugging the monitor to my iGP the system is stable.

 

[Hlias Anton]

check your gpu temps when you gaming, usually the pc is going in sleep mode when the gpu in on high temps.

 

[Andrei Bogorodski]

check your gpu temps when you gaming, usually the pc is going in sleep mode when the gpu in on high temps.

As i said, my temperatures are all withing the normal range.
CPU wont go above 60
GPU wont go above 80 (for 295GTX it normal)

also the GPU dont have the time to heat up, as sometimes the pc crashes after like 1 in game minute...

 

[Hlias Anton]

Try to downclock your gpu and check if the problem continues.

 

[Andrei Bogorodski]

Try to downclock your gpu and check if the problem continues.

how do i downclock?

 

[Hlias Anton]

Try to downclock your gpu and check if the problem continues.

how do i downclock?

from nvidia control panel, performance/ device settings.

 

[Andrei Bogorodski]

k i downclocked it, also i used asus gpu control panel to increase the fan speed to 100%,
still got the same problem.

Also i tried to remove 1 DDR stick, or place it into a different slot, didnt helped.

 

[Andrei Bogorodski]

bump?