Hi! I decided to go for a 21.5" iMac on refurb. I got the basic configuration Quadcore i5 2.7GHz, 8gb and 1Tb 5400rpm hard drive. I wanted to have the advices on upgrades I can make to it.... I'm thinking about going to 16gb of ram in the next few weeks... Will it change something? Has anyone done it? And then I'm thinking about getting an SSD (Samsung 840 Evo 500gb). Is that a good idea? Is it compatible with the machine? D.