Is there any actually good PC diagnostic software?

[Shrappy]

My nephew brought me his computer saying that it is not able to play his games that up until recently have been ok. Randomly shutting down, and just not performing the way it should or used to. Now this is a rather old pc and I understand that. However I would like to help in any way that I can, but I don't know where to start or how to diagnose any issues that may come up. Any help would be appreciated.

 

CPU: AMD A10-6700

MoBo: Gigabyte GA-F2A88X-UP4

RAM: 12gb (3*4g)

Graphics: AMD Radeon RX 580

PSU: Cooler Master Extreme 2 525 

Windows 10 Home x64

[Shrappy]

I'm looking for diagnostic, not benchmarking.

[Bingus_Bongus]

AIDA64 is what comes to mind pretty quick, and some version of PC Doctor service center that can be downloaded for free and flashed to USB.

 

Other than those, the Windows Event Viewer is the biggest taddle-tale of system problems, especially hardware ones. Are you able to post some screenshots of some of the errors without the system shutting down?

[Avigaming_]

There is no all-in-one diagnostic software however I can recommend something like HBCD pe or medicat as well as memtest86.

Troubleshooting/diagnosis is usually a matter of elimination until you find the issue (when hardware is suspected at fault) and if everything is fine on its own then we usually check if some things just don't want cooperate. AIDA64 is a great stress testing tool as well as event viewer which does usually give insight in why something went wrong.