I don't know about Windows 7, but I am runing Poser4 with Windows XP64 without any problem.

Another thing is the performance of Intel 64 bit CPU running 32 bits applications. AMD64 runs 32 and 64 bits applications with exactly the same performance, but in the past Intel64 run 32 bit applications in an emulation mode with degraded performance. I don't know if this was fixed today with the latests Intel's CPUs

Stupidity also evolves!