We have several new desktop PC in our office with Windows 7 Pro and the prescription writer function is no better than the Windows XP Pro machines.  Server is Dell T300 with SBS 2003.  I eliminated the hardware acceleration and got pretty good results in version 6.0.9 but version 6.1.0 is even slower.  The last version 5 prior to version 6 worked great.  Of course, we upgraded for the Meaningless Use which has added a lot more time to our workday.