I have a workstation with two 4 core Xeon processors and xtop only uses ONE core. Xtop does not have to use all cores, but getting more threads going would help a LOT with my large assemblies! The Simulate solver manages to utilize near 90% while solving, but even that goes back to one core for much of the solution process. It would seem that PTC is feature driven not process driven!
The CPU utilization is the bottle neck, my system has:
A Z800 HP workstation with two 3 GHz Xeon processors
12 GB of memory
A Nvidia K5000 graphics card
Two 15000 rpm Seagate Cheetah hard drives configured as a RAID 0
LSI MegaRAID SAS RAID controller
When students ask me about Creo I tell them that it is feature rich, but it can be slow.