The only overclocking I do is the one available directly from the Tweak II GPU application ( OC, gaming or silent)

On the other hand I read that the voltage were not the same with the silent firmware, that can explain also the difference but as I had not noted the voltage before I do not know if it is that.

Black screen will be GPU instability. So whatever boost clock and voltage the card was running at on the previous configuration, it wasn't entirely stable.

It's really weird my problem, after installing the bios I didn't have any problems yesterday, I test with several games, and I launched 3Dmark in stress for several hours.

My computer remained on all night and this morning impossible to wake the screens, forced to do a reset, yet the computer was working because my automatic backup worked normally this morning at 8 AM and no error in the event viewer.

The disc led was blinking normally, but it was impossible to make a teamviewer maybe because the video card wasn't working anymore.

I'll change the power supply on Tuesday to see if it's that but I really have no idea what the problem is. My computer was working great until Friday night when there was the first problem.

I can't find the problem because it doesn't appear often like before I install bios 86.02.39.00.23 quiet but I don't know before the one I had.

With the old video bios as soon as I started a game it crashed.

It's hard to know if it's a video card problem or a power problem. if anyone has an idea I'm very interested.

You can test your GPU card in another machine.

You can do the same with your PSU, though results will be less conclusive unless it's dying hard.

I'd go through the usual troubleshooting methods first. Re-seat the GPU card, clean the PCIe connectors if needed, check all power inputs are firmly secured (at both ends if the PSU is modular), Clear CMOS and strip the system down to minimal hardware (and one DIMM) then build and test upward one piece at a time until a hardware fault can be isolated/replicated or just magically seems to fix itself.