For some reason ever since about a month ago, I’ve started getting random FPS drops. It usually drops from like 100 to 60, but it’s so frequent that it causes a lot of lag, and makes it really hard to play. As everyday goes by, I’ve noticed that it’s been getting worse and worse, and it especially happens in comp. I haven’t experienced these issues in any other games before, and at the start i was able to run overwatch on all ultra settings at a constant 90 FPS, but now it’s super choppy and I’m running it at all low settings with horrible FPS.
I’ve been getting the exact same issue, and around the same time I upgraded my monitor to support higher refresh rate (60hz to 165hz), and my other components aren’t exactly lacking either (GTX 1080, i7-4770, 16GB RAM), so it isn’t just isolated to you
Same issues and one of my friends has a GTX 1080 and his framerate drops to 30fps sometimes…
Same issue here. I did have a driver update a week ago which did fix it… up to now. And now these sudden drops are back. So really weird stuff ever since they introduced OWL. I see they have their priorities… 
Same issue. I was playing like 3 month with Gtx 1080ti Low settings 200fps locked. Now the Fps drops to 150 that cant be real i was thinking that my Graphic was broken or something. It can be the overwatch update or the Nvidia update with that 391.01 Driver Who knows.
Same issue here. Its so annoying and ive done everything in my power to try and fix it but nothing works.