Okay.. so I'm reading to upgrade my RAM under Lion to 8GB... its causing stuttering videos etc.. sometimes with MKVs etc. So, how do I do this? Has anyone got a guide? but more importantly.. what RAM do I buy? could someone give me a UK LINK!!! seriously, I tried this last year with a different mac laptop and bought the wrong RAM and just left it. :'( don't wanna make the same mistake again. Thank you so much guys!!