It was 59C under a load. As high as 67 today after a few straight hours of gaming. Sounds like it's not a problem.
The CPU thermal paste looked good. Fully covered without spilling over the sides. Of course, since I pulled the heat sink
anyhow I went ahead and replaced the paste. Still doing fine.
Started getting the stutters today after a few hours of Destiny 2; took 15 minutes off, turned settings all down to medium or high. Been pretty solid since then. Video card memory usage was at like 79% with the previous settings (of 3GB), and none of the CPU cores was getting pegged.
***EDIT***
So, finally did it again just a bit ago (I'm on a different machine now). FPS cut to 27-37, and felt worse than that. Nearly unplayable. If you're familiar with Destiny 2, it was just at the end of a public event (the one with the Fallen servitor) in EDZ, and there was a lot going on. 3-4 other players there, one of 'em had dropped Nightstalker super and grenade. Servitor blowing up. Etc. Got the single-digit framerate stuff for a few seconds, followed by being stuck at 30-ish.
So that Open Hardware Monitor was a bust. Installed a different one (mentioned here in a previous comment; thanks for the recommendation!). But by then, temps were pretty normal. CPU temp was falling from 35.0 by the time I got it installed and running. It DID record a total CPU usage of 92.0% and 100.0% on one of the cores, but not really sure what that was about.
SO, gonna let it sit and cool off overnight. If it's still being weird in the AM, after 7-10 hours of being shut down at room temp, then I'm gonna be like 99% sure I've got a software/system/driver problem. If it's back to normal, then I'm gonna run it with the new monitor running in the background and see what it does.
It had been running for 9-10 hours straight, with breaks from gaming lasting 7-30 minutes, when this started. When I had the case open, I was kinda shocked at how little space there is between the GPU heat sink and the bottom of the power supply. The graphics card itself seems to mostly block air from coming from anywhere other than the back of the card. This just bums me out though...
Edited by Not A Real RAbbi, 15 January 2018 - 07:54 PM.