Every couple days, my Mac will simply freeze for several seconds to a few minutes. Any audio stops playing, and the mouse stops responding. Then it's back to normal. The 99.9% of the time it's behaving normally, it's just as snappy as the day I bought it.
How can I figure out what is causing this?
My Mac is getting old so I accept that it could simply be normal (if excessive) lag, but I don't know what aspect of my system I would need to upgrade to mitigate or minimize this. More RAM, faster RAM, faster GPU, more VRAM, faster SSD, faster CPU, more cores?
I'm on a cheesegrater Mac Pro running Sierra, so it's not the newest Mac in the world, but it has 16GB RAM and a mostly-empty SSD and quad Xeons, so it's certainly not the slowest, either.