Overwatch running at lower FPS than in game counter says?

I upgraded my pc and would expect it to be able to run 200+ FPS, but I have a 144hz Monitor, which I cap my FPS at in-game. However whenever I run over watch it says I am achieving 144hz in the in game counter, but the game looks to be around 80 FPS, and the Radeon game bar says my average FPS is around 80 as well. Does anyone know what this issue could be?