STAAD.pro v8i multithreaded?

Is STAAD.pro multithreaded?  I've ran a couple comparisons and found that changing the processor affinity to force the basic solver in STAAD to use only one core didn't affect the performance much, so it may not be. 

How does the advanced solver compare to the basic solver?  What is the expected reduction in processing times? 

Also will I see processing time reductions using a quad-core processor rather than a dual-core in either the basic or advanced solver?

Thanks for your help,

Ben