Both of these were causing a weird, random stutter. It sounds kind of robotic, it usually only lasted a split second and would do it a few times in succession, but other times it would last much longer, ie watching a video on Youtube the voices would become all robotic sounding and slowed. Sometimes it fixed itself after a minute, sometimes I had to reset. Went back to 18.5.2 and the issue went away completely, but of course AC: Odyssey runs like crap now. Any help appreciated!
Might be worth noting both times I tried to install (I always do a clean install), after the first reboot the installer would freeze up about 1/3 of the way through, but after doing a reset and trying again it went through no problem
16gb ddr4 RAM
Edit: Wouldn't you know it, it happened today on 18.5.2. So while the issue undoubtedly improved for a few days, it's not gone completely.
I did recently install a new motherboard so could be related, but I'm pretty sure everything else is up to date?