I use a dual boot system. I installed the extra 500gb drive for xp64. I have everything installed to 64 bit now and use the 32 bit more for storage. Everything runs better on the 64 bit. The only thing that doesn't as far as I know is Quicktime and to tell the truth, does anyone really care? My DivX now plays .mov and mp4. Al my 32 bit apps work a little faster and all the ones that take advantage of 64 bit run great. I don't use ZBrush, but my Modo runs so much faster on 64 than it did on 32 and it is still 32 bit, for now.