same here, less than 40 fps in Overwatch, although I get around 120fps when running it native
System: R7 1700 & GTX 1080 ti
there seems to be a known issue with NPT:
https://community.amd.com/thread/215931
turning NPT off boosts the GPU to the expected performance, but the system becomes almost unusable for me outside of games with stutters and hickups (even with pinned cores)
also relevant: