Not a thorough test by any means but:
I was running Poser 2012 with no SR with no problem. Admittedly, I wasn’t stressing it too much. Stock SSS from one of the rendo vendors.
I installed 3.1 and the program started crashing. Sometimes after the 3rd or 4th texture change. Sometimes after a render. Always when exiting Poser.
I turned off ReadyBoost and it seems to be working fine now.