I'm using 6.5 on my new computer (featuring RTX 100) and on my old Compaq Celeron 667 and surprisingly all the effects I have tried (Premiere transitions) have played in realtime (sometimes not the smoothest, but play none the less). I'm sure if you had a P4 1.5 or greater you would be fine. I don't think you need a dual chip setup for 6.5 but the faster the chip the smoother things will play, but a 1.5 or possibly a 1ghz should be sufficent enough for realtime effects to work. I would definatley recommend the upgrade from Premiere 6.0. Good luck with your decision.