https://bugs.winehq.org/show_bug.cgi?id=44315
--- Comment #7 from Ganni87 jonfarr87@gmail.com --- (In reply to Henri Verbeet from comment #5)
(In reply to Matteo Bruni from comment #4)
I think you're spot on. It looks like wine-staging 2.0 was the last version with the CSMT buffer map optimization hacks which, in some cases, could reduce CPU-GPU synchronization significantly and thus improve game performance.
We'll probably introduce something non-hacky to the same effect in wined3d at some point in the future.
It's a bit awkward to have this as a bug against the Wine product though, since it basically amounts to "D3D performance could be better". Wine never had those hacks—and for good reason—so GW2 performance in Wine shouldn't be any worse than it ever was. (If it is, please do a regression test.) At the same time, it doesn't seem al that likely that Staging would be willing to take this as their bug and work on bringing those hacks back in an acceptable form.
Unfortunately the performance loss is very much noticeable especially when you play the same game regularly for over 5 years.
As I've mentioned in my report, the rest of the games I play weren't affected. If there's a way to apply this hack manually to modern Wine versions I wouldn't mind building the binaries myself.