is poser installed as a 32 bit application ?  it should auto install to the program 32 bit files, and it certainly sounds like driver problem,..how many processors are you assigning?  check task mgr and make certain that poser is assigned both processors.
mine runs like a dream.  sorry to hear.  lots of drivers and stuff at planet 64..you might have to install and re install several times...i use a dual boot.  good luck.