Windows 6 64bit, Nvidia Quadro K4000
Broken: Newest official 2.78c (hash e92F235283)
Short description of error
The more I have threads enabled, the slower the texture painting performance is.
I get best performance when setting the threads manually to 1, from render settings.
Maximum I can have is 24 threads.
Exact steps for others to reproduce the error
Make a cube, unwrap, make new image (4096 x 4096), enter texture paint mode, start painting.
Go to render settings and experiment with different thread settings.
My other possibly related settings:
Window Draw Method: Triple Buffer
Region Overlap enabled