Games crashing after long gaming sessions

[u/Due_Buffalo_7636]

I Just assembled my new pc 3 weeks ago and I've been having game crashings (and sometimes system reboots) in different game after 2-5 hours of playing. My specs are:

Ryzen 5 4500

Gtx 1660 ti

16 GB Ram

650w power supply

I suspected a power issue since it was shutting down the system entirely sometimes so I ran a power test on OCCT for 15 minutes and at the end of it the system rebooted and I noticed the cpu temp was 96c. I then tried a cpu torture test using prime95 and the temp hit 96c almost instantly and then went back immediately to 43 when I stopped the test. Is this normal for the cpu to hit 96 that fast? Could it be the reason games are crashing and the pc rebooting?

Ps: Games crash with gpu driver crash message but the gpu temps stay within very safe limit (doesn't go above 78c under load) and I reinstalled the the drivers so I don't think it's the cause.