Ram = Random Access Memory. Which in turn gives more memory to the programs your using. Just XP alone needs atleast 256 to run o.k. The more RAM the better proformance in games, browsing and muli tasking. So 128MB will give you more memory, which in turn will give you better performance. My machine runs 1GB. And I don't have any problems. If you playing on-line game I would get at least 512 all together. Hope it answers your question
