Here are the specs for your laptop. Your ram runs in dual channel mode which means both ram chips must be identical for it to work in dual channel mode. You should use two 2 gig chips to maintain dual channel mode. 32 bit operating systems can only utilize a little over 3 gigs, so some of the memory will be wasted. Unless you're having a problem with it, let it alone. You won't see that much improvement with another 2 gigs. What is the purpose of upgrading the ram?