Question Problem GPU cannot benchmark & play certain games

[swa69er]

My Z390 motherboard dead so I have turn back on my older PC
at first everything went okay with my old Windows 10 settings, play games, adobe, and many. Just like my newer PC but without SSD

I don't what comes to my mind, feels like to reinstall Windows 10
and then suddenly Rainbow Six Siege cannot load main menu, all GPU benchmark (Unigine Valley, etc) hardly run over 5 seconds
The only games that work is Company of Heroes 2, but when game end, crash!

Last seen FPS in Unigine Valley was 100fps, but I don't know what happened, it is just crashed (closed)

 

[oldcracc]

Your PSU might have failed, what PSU do you have?

 

[swa69er]

Your PSU might have failed, what PSU do you have?

found out this bcdedit /set testsigning off on CMD solve my problem
but after Windows 10 Pro latest update, I have to do this every time I turn on PC

what is it? I mean in detail. I know it's a way to disable driver signature enforcement but why it can cause game crash and benchmark not working