Most of the time Sandstorm will play at my locked 60fps, but sometimes, maybe in certain areas of maps, my frame rate drops down to 40-50, even though I can see my GPU is little more than 50% in use. And the CPU is no where near full use, or though if I recall core 1 can at times being hit quite hard?
I've even lowered detail and no difference.
I'm on I4790K with a NVidia 1070, on a 2560X1440 monitor...