we have already discussed (and finally solved) the problem of bitblt being slow:
Now I have updated to 1.5b4 and I again get this problem. BitBlt for full hd resolution takes about 300ms (see attached screen shot).
This screenshot was done with your image 1.5b4, registry only modified to increase screen resolution. ipumem increased with configblockeditor.
I also upload my blttest project.
Are you sure that all modifications done last year have found their way into 1.5b4 ?
Or is something wrong on my side ?