I can't help I don't use the usb option and therefore don't have any experience ( as I can recall atleast ). I just set up the c2d with the vmware appliance and the free vm player, it's running a 2669 but I got problems monitoring it in fahmon, and since I don't have a network connection between that pc and this one I can't monitor it with fahwatch. It's at 6% though and using all ram I got on that machine for a single instance ( eg xp 32bit pro, 1gb ram all allocated ( +-500 if that going to vmplayer ) from 1gb total ).

Btw now I also know what you mean with having no option to adjust the ram for the vm, only vm workstation gives me that option. Think maybe you need to change the config to not allow big wu's and try to get some less demanding one's in ram that way ( though I think running without -advmethods would be the best option )