I'm so not an expert ! I really don't know. I also have two drives, but the second is only for the paging file. Before I did that I had all kinds of problems with Poser and with P Booost. Whether that is a solution for everyone or just on my particular system I couldn't say. Are you making sure to leave your Poser library on 'Switch Banks' before you try PBoost ? That was another problem I had :-)