https://bugs.winehq.org/show_bug.cgi?id=42460
--- Comment #7 from Krzysztof Machura krzysztofmachura1@gmail.com --- (In reply to João Vitor Verona Biazibetti from comment #6)
Confirmed here. This didn't happen back in 1.8 version. Has been happening since... 1.9 I think? Or 2.0. IDK.
I'm using wine-staging, version 2.0. Tried disabling all patches (CSMT, etc...), the same thing happens: after ~25 min of game, the FPS starts decreasing. DRASTICALLY.
I'm using Fedora 24. I have a Intel HD Graphics 4000, Mesa. Restarting the game brings the FPS back, but... it's annoying.
Did you try limiting FPS ingame to 60? I got pretty good results with it on. I think it is independent from the wine version. I believe it was introduced by LoL patch, but there is no real way to check it.
About Nvidia I checked it on Nvidia+Windows+wined3d and it works great with no degradation, atleast not on level of which happens on linux+Nvidia binary blob, where i drop to 30 fps after 5 min.