I've just installed this http://www.mushkin.com/Memory/Apple/976643A.aspx on my 2.4ghz originally 2gb ram macbook and I've run into a lot of problems pertaining to lagging. Firefox is consistently beachballing, which freezes my computer for about 30 seconds. I thought this was a FF bloat issue so I tried clearing history, no good. Switched to chrome, which is much lighter than FF, but this still occurs. I've tried reparing permissions too. What am I missing? Is this RAM bad? It should be faster now with 4gb instead of 2gb ram.