So I have a late 2012 27" iMac. It has 8GB of RAM, a 2GB Graphics card, the i7, and a fusion drive. While it used to perform pretty well it has been letting me down lately. Boot times are pretty lengthy, and once it boots up it takes awhile to be usable. It also slows down when using Audacity, Gimp, Garage Band, or iMovie. Is there anyway to find the cause of these issues? I was considering buying more RAM, would that help any of my issues? Can I buy 8GB more to make it 16 or should I buy a 16GB set. Thanks!