A gfx card is almost useless anyway for most
demos which are mainly AGA.
My advice for watching demos and obtaining an
acceptable workbench speed:
Blizzard 1260, 64 meg FPM SIMM can be found
for under $20 at oempcworld.com (there are a
million good demos which take advantage of an
'060)
SD/FF (you want an internal for best video
quality)
A couple of hacks to speed up video performance
under AGA: FBlit, FText and BlazeWCP (aminet)
They make a *huge* difference.