Yes. It's a complex situation but with 3GB of RAM and I assume a dedicated graphics card RAM you were probably wasting your time in the first place.
Vista Home premium will only recognise 4GB of RAM including the RAM in your graphics card. In addition unless your flash pen is optimised for RAM it will perform sub-optimally. For flash to perform optimally it will require a flash which has fast read/write over the whole range rather than as a single event. Many such cards are marked optimised for Readyboost rather than the standard flash devices.