I will be upgrading my daughter's laptop memory from a 2x512 configuration to 2x1 gb. She is running Vista so another gig should help. Right now I can get both Crucial and GSkill in 2x1GB sets at good prices. The Crucial is CAS 5 and the G.Skill is CAS 4. Is there much of a difference between the two that will be noticible in normal application work? Her system is for school papers, online research and browsing, and IMing; plus she'll watch DVDs from time to time. This is not a gaming laptop. She has her PS2 to do that. Thanks.