You will see a larger difference in performance by moving from a slower hard drive (like the Seagate Barracuda IV or a Maxtor D740X) to a faster drive like the IBM 120GXP or WD1200JB...than you will from 256Mb to 512Mb. Simply be replacing your hard drive, game levels will load 30-40% faster...you do not get that same benefit in moving from 256Mb to 512Mb RAM.