Actually, win 7 home premium 64bit supports up to 16GB(a limit set on that version by microsoft) and 128GB for more expensive versions( again a limit imposed by microsoft). Echoing ram usage, 8GB is plenty for most gaming and light work, but heavier workloads/heavy multitasking can make use of more ram. If you happen to play minecraft, it can use as much ram as you can throw at it.