Well I have dual boot, WinXP and XP64...Poser works fine with XP64 but it works under 32 bit emulation, thus slower. Hope a 64bit patch comes before Poser 7 as a service release, at least for the firefly engine because I have seen Cinema 4D engine render under XP64 with Athlon 64 (cinebench benchmark is 64 bit) and it is truely unbeliavable... My 160$ OC'ed venice 3000+ renders %75 faster than an P4 extreme (around 900$)...I cannot imagine what an X2 can do under XP64 with a 64 bit rendering engine...