I never checked this really before updating to SL, but just noticed this when I was working on my XP Bootcamp partition. I recently purchased a new 13" MBP and upgraded the RAM to 4GB through crucial. In leopard / SL it shows up fine, but when I look at my diagnostics in XP it shows up something like 2.67GB. Has anyone else had this issue... and is there any way to fix it? Thanks in advance.