XP pro (2002) Service pack 2
Intel p4 2.53GHz 512 Mo
Gforce FX 5600
(I should try this snippet on an AMD 3000+ and Geforce 6600 tomorrow.)
I had noticed differences between graphics cards. But had not enough feedback with gfx bugs (just incompatibilities with graphics modes bellow 640*480 and frequency's refresh rate > 60 Hz, or smoothed fonts with clear type that can bug drawfill and getdot)
2D performances too, mainly when it's about moving huge bitmaps (Maybe the ramdac).
I hope it wont be a nightmare to fix drawscroll instruction, especially if I'm alone with the problem ;P
Some people I know should be crazy as I am about all the improvements you said.
Better timer instruction and improved draw commands sound marvellous. OLALA!