I don’t think your hardware is the problem. Since the “Ashe Update” a lot of people are having Frame drop problems (including me). Still waiting for a fix.
Other Topics about the problem:
https://us.forums.blizzard.com/en/overwatch/t/frame-rate-issues/254486
https://us.forums.blizzard.com/en/overwatch/t/another-day-still-can-t-play/256256/3
https://us.forums.blizzard.com/en/overwatch/t/huge-fps-drop-after-update/250529/17
https://us.forums.blizzard.com/en/overwatch/t/frame-rate-is-very-low/256437
https://us.forums.blizzard.com/en/overwatch/t/significant-fps-drops-after-ashe-patch/255690
https://us.forums.blizzard.com/en/overwatch/t/huge-fps-drop-in-game/255292