Readyboost is a so called cache thing barhs the Readyboost is a very straight forward feature. If the thumbdrive can't be used it won't allow you
to even used it.
But if the thumbdrive is useable it will ask you to choose how much space to use for it. Best dont store anything important inside because if anything happeneds xD GG
Lastly will like to say,no point using the readyboost if you have only 1GB/512
because it wont squeeze much out than increase the ram twice.
because rams now are cheap if ya buy a thumbdrive it will cost roughly the same price so get the ram instead of thumbdrive if you need the speed