You wont see a huge improvement going above 1600 (its pretty much the standard now anyways).
You say you want to improve "installing windows"... Thats wierd because most people dont reformat daily. As far as games goes, most only use 2-4(maybe)GB anyway. So installing another 8 GB wasnt going to net you a performance increase anyway.
16gigs is only utilized when rendering, encoding, or editing (CS6)