The latest version of patch 4a is in the experimental directory. It should allow your problem video cards to work.
Yes it does, all is well now.
It does, however, have the problem with a virtual screen getting messed up when choosing another fractal type through the <t> screen.
Yes, I can duplicate this. It shows when using guessing, but not passes=1. Maybe that's a clue. Guessing reads the screen, but passes=1 does not. I'd look and see if the pixel reading routines need something for virtual mode support.
This appears to not be a problem with sxdots and sydots as I had first suspected. OTOH, I'm clueless (again).
Not too cluesless, because you fixed the problems with my video card. Maybe this comment is for Charlie. This is purely a personal preference, but in virtual mode often the screen scrolls when I don't think it should when I am moving a zoom box. If the zoom box can move, that's what it should do. The fractal should only pan if the zoom box hits the edge of the screen. Tim