FlowSim in SW2011 SP5-EV

Today I installed SP5-EV to try and see if a SW Sim problem we had been having was fixed, and fortunately it has been.  However, FlowSim now seems to be incredibly slow to use.  It is a resonably complex assembly, but it has taken me around half an hour in total to simply add lids to either end of the main pipes, not to mention the 20 or so minutes it took to load the Wizard in the first place.

Has anyone else installed SP5-EV and if so, have you encountered this same problem?

For reference, I'm on a HP Z600 running WinXP x64.

SolidworksFlow Simulation