[Bug 44315] Buffer maps cause CPU-GPU synchronization (Guild Wars 2, The Witcher 3)

https://bugs.winehq.org/show_bug.cgi?id=44315

--- Comment #35 from mirh  ---
Pba was originally created by comminos for World of Warcraft actually. 
(and if I really had to say it: I think it's almost basically the only obstacle
for wined3d for sacred "dxvk level" performance)

My theory was that people were reporting "different results" because
GL_ARB_buffer_storage is bugged to hell on radeon/mesa. 
But comment 17 of yours (contrarily to others, and my narrative, duh) claimed
even for nvidia pba sucked.

After this last testimony it makes for *a lot* of improvement though, I am
really really wondering whether you couldn't have done something wrong yourself
instead. 
If you could re-check....