Hi, I have a late 2012 21,5 iMac and now I get to that point when I feel my computer unusable sometimes. Spinning beachballs and bouncing icons on the dock for 5-10 seconds (it takes more than 30 second to launch PS)... I clean installed Yosemite and currently I am using El Capitan Public Beta, but it's still very slow in app launching. So I started thinking about upgrading my Mac. The processor and RAM are fine but the 1TB HDD isn't the latest technology. Do you think an SSD upgrade can solve all of the problems or should I sell my Mac and get a completely new one? If the SSD'd work, whick one? PCI-e or Sata 3? And I also read about a fan issue with iMacs and I don't know if a fan control app can help. (Sorry if my English isn't the best)