I have not tried P6 under W64. I suspect the "3d rendering" claim from Microsoft is for real-time rendering on the 3d card, assuming a 64-bit driver taking advantage of a wider bus. Interestinly, it looks like there's a mode under W64 to allow 32-bit apps almost the entire 4GB address space. Most 32-bit apps are limited to the bottom 2GB, but a linker switch allows access to the third gigabyte. This W64 mode is supposed to give access to all but the top 256MB or something like that. However, I think the app has to be linked with /LARGEADDRESSAWARE and not have any internal assumptions about memory ranges. Only the Poser programmers can tell us if that's so. (I dream of a 64-bit multi-core HT system with 16GB of RAM and a Poser 7 that will take advantage of it.)