On Mon, Apr 17, 2017 at 10:05:37PM -0700, Roderick Colenbrander wrote:
Depending on source, destination format and some other things it may get accelerated e.g. by winex11.drv to xrender. Assuming xrender is picked, it could be that your drivers are not accelerating this situation.
By default this won't happen and the stretching will be done in the dibdrv. If you're running with the X11 driver, you could try adding the registry key
[HKCU\Software\Wine\X11 Driver] "ClientSideGraphics"="N"
Huw.