Like some of you, I too found Grim Dawn weighing heavily on just one CPU core while the others are twiddling their thumbs most of the time. Then I remembered that some games in the past have had issues with Hyperthreading.
To cut to the chase, apparently so does Grim Dawn. Using the Task Manager to set CPU affinity to every other core starting with core 0 checked and core 1 unchecked lessened the clogging on core 0. Instead of at or near 100% core load in Devil’s Crossing right after loading the game, I’m now at a comparatively very comfortable 60% to 80%, and that’s with all game settings maxed out, including 8xAA and 16xAF. The overall effect on the game when playing is that I’m now at 60FPS more often than before, though still not always.
If you want to apply this method regularly, I’ve written a tool that applies the changes to CPU core affinity automatically when it detects Grim Dawn. Both executable and source code are on GitHub:
Since I’m not yet allowed to post links, you have to copy and paste the address and remove the space.
Another thing I noticed was the game stuttering while loading assets when entering a new game area. Opening options.txt (located in Documents\my games\Grim Dawn\Settings) and setting maxResourceThreads = 2 (default was 1) lessened the effect a bit.
Let me know how this all works out for you.
System info for comparison:
2600K Sandy Bridge CPU overclocked to 4.5GHz
Nvidia GTX 780 CPU OC’d to 1150MHz
Samsung 850Pro SSD
Attachment: CPU Affinity.jpg