My average fps in black death track went up from 25 to 27 just using a 4gb flash drive exclusively for ReadyBoost on a core2duo 3,3ghz, 4gb ram, ati hd6770 1gb. I have only one hdd. os Windows7 64.
Those are the settings i use:
I always use readyboost but this time i unplugged my flash drive and i noticed the performance hit, especially in missions above London. Without readyboost it lagged.