I have a mid 2009 2.53 15" MBP with 10.6 4gig RAM and the 5400 hd. I'm currently running parallels and need a performance boost. What will get me the most performance boost in this configuration? Upgrading to 8gb of RAM or a 128gb ssd? Both will run 500-600 which is about my limit for now. I'm going to do both at sometime, but I just would like to know which will give me the biggest immediate performance boost. Thanks!