Slow emulation of StretchBlt

[andrea]

Hi,

I am looking at the performance of AppleWin (a 32 bit app) in Wine and have come across this 
function StretchBlt which seems to be much slower in Wine that in Windows 10.

The call looks like this

StretchBlt(
    			hFrameDC,
    			xdest, ydest,
    			wdest, hdest,
    			g_hDeviceDC,
    			xSrc, ySrc,
    			FRAMEBUFFER_BORDERLESS_W, FRAMEBUFFER_BORDERLESS_H,
    			SRCCOPY);

With typical values

xdest	0	int
    	ydest	0	int
    	wdest	1120	int
    	hdest	768	int
    	xSrc	22	int
    	ySrc	17	int

#define  FRAMEBUFFER_BORDERLESS_W 560
    #define  FRAMEBUFFER_BORDERLESS_H 384

In Wine they take 20x the time in Windows 10 (running inside a VirtualBox).
The consequence is CPU utilisation 20x higher in Wine than Windows.

I am running wine 2.5 in a 64 bit Fedora 25 machine.

Does this ring any bell?

Andrea