So I have a 2008 Macbook Pro. It works but is definitly starting to show its age. Right now I have OSX 10.6.8 installed and was wondering if upgrading to 10.9 would give it much of a performance boost. The area I have the biggest issue with is in running virtual machines. I have Parallels 6 and noticed that when I went from OSX 10.5 to 10.6, all of my VMs starting running super slowly. If I upgrade to 10.9 I have to upgrade to Parallels 9 as well but would rather spend the $50 on the Parallels upgrade than the $2000+ to get a new computer. Any thoughts?