I'm getting 1400/1200 after a fresh fsck -fy. When it gets down to about 1000/800, I boot into single-user mode and do the fsck -fy again. I gotta do that about every three to four months.I am in the same boat as you, I need Sierra for stable Nvidia CUDA drivers and I never want to have the 'screen burn' issue again. May I ask you what speeds you are looking at when using the SM951?