Something that big has an underlying cause.
You are probably not out of CPU since it didn't tell you that.
More than likely it was some other thing that caused it. Exactly what? IDK.
Check the drivers and update as needed. Also run some scans. AV is a good place to start and then follow with a registry scan. And a nice disk defrag wouldn't be a bad idea. All the basics just to be sure.
It's amazing the number of things that can get into and can go wrong in a system that will cause such issues.
Good luck.