I just tested a 250G Vertex OCZ in a 8 core 2.26G (2009) MacPro with ATI 4870 card and managed 6 layers of AIC at 1920x1080 25fps... not sure if its the new architecture or faster vertex drive - so more testing to do (if i ever get time)

OCZ do seem to be the best value for money (even at 250G!...)

Incidentally - ATI 4870 does support analogue (VGA) on both ports with the relevant 'display port' and DVI-VGA adaptors. But only Dual-Link DVI on the 'real' DVI port. The 'Display port' is only single-link. No adaptors are included with the card pre-installed in a mac - so you have to purchase your own!!

Am going to try an Nvidia 880GT in a 2.26G (2009) MacPro tomorrow to see what happens...

Simon