OpenBSD 4.3 came with xf86-video-ati 6.6.3, 4.4 comes with 6.9.0.
That's quite a big diff.. it could be something that changed there, or there could have been some kernel wscons/vgafb changes.
The fact that you're experncing problems on both 4.4 and -CURRENT is unfortunate, I notice that you have sent an email to the PPC list, but that list doesn't appear to be high volume.
Consider using sendbug(1) in 4.3, or 4.4 if you still have it installed.. otherwise, send an email to @bugs or @misc.
Sorry..
