We have an iMac 8.1 which seems slow (lots of beachball) despite 4GB memory (should be enough for mail, web and regular everyday stuff) and a 50% full 500GB hard drive. It's running OSX 10.6.8. I recently read some articles on the iMac's design not being the best to combat heat buildup and to make things worse, dust builds up inside as well. Finally, a mechanical hard drive generates a lot of heat, so thinking an overheated hard drive could be the culprit I installed the free version of Disk drill which can display the hard drive temperature in the menu bar. Likewise I installed SMC fan control and found out the hard drive temperature was quite high (right now Disk drill says 42 C while SMC fan control says 36 C -I have no idea why they show different numbers since I assume there's only one temperature sensor, but despite this I feel the temperature is too high -anyone know?). So with the iMac getting close to the ending of the warranty period I'm thinking that replacing the hard drive with an SSD could solve a lot of the problem -what do you think?