Here's my dilemma.
I have 2008 MBP, 2.6GHz Core 2 Duo, 4G RAM, 7200rpm HD; Wife has 2014 MBP, 2.5GHz I7, 16G RAM, SSD.
Her's FLIES!! Ever since I updated to Yosemite, I CRAWL. :( (Under Snow Leopard, it was fairly speedy....and NO, I won't go back)
Although Apple says 4G RAM is max...