FLASH MEMORY as ram?

the aim of ram or cache or any memory is to store data and retrive it as fast as possible so you don't feel the delay of data transmission.. cache memory is attached to the processor so it is very near and take no time nearly to retrive data.. the ram is the second nearest storage for the information and it is considerd fast in retriving the data too.. but what if your cache and ram are not enough to store all of your running data?! in this case part of your hard is converted automaticly as something called virtual memory..it is large storage but far from the processor so there may be a noticed delay.. usb is way far than the hard disk in the communication proces so using it as ram is very useless..it will have a noticable delay and will not help.. i hope i helped you..