win10 freezing randomly

[Reizo]

Hi guys, so my PC has been randomly freezing, sometimes 3 times in one day and sometimes a month without freezing at all. sometimes it freezes on the windows loading screen, sometimes right after loading the desktop and sometimes after some use while in browser/game etc - random.

 

After some troubleshooting, I came to the conclusion that it could be because I accidentally added ram sticks of different timing (another possibility is probably some sort of software problem). I don't know much about RAM timing and couldn't figure it out on my own so I'm attaching some screenshots. To be clear it's an old rig that I got from a friend and upgraded with SSD and extra RAM (win10, MOBO: AIMB580, CPU: i7-860, GPU: Palit GTX660).

Here:

https://imgur.com/a/8Qgkkow

 

If you could shed some light or else have another idea for why it freezes, I'd be happy.

 

Thanks a lot!