I can play MHW with 140 FPS on high settings with 1080p.
However this game, in the last 2 updates (starting from the one with the Unity engine upgrade) the FPS has become significantly less. Dropped all the way down to 30 FPS.
Windowed / Fullscreen, changing the resolution, checking / unchecking all graphic options basically doesn't affect the FPS at all. I think it's the CPU that is being the bottleneck.
After last update I couldn't even run the game in Windowed mode anymore, constant 20 FPS + stuttering.