"Saving your head off was completely unnecessary in P4." Lucky you. That wasn't my experience through two Macs and several upgrades. I haven't taxed P5 enough yet to know, but so far the cancel button has been responsive. How populated/overpopulated are your scenes? Are you leaning on Professional or tweaking Draft to achieve similar results (now that I've figured out how to get antialiasing without fullbore Professional, life is good and rendering times are actually comparable to default Draft)?