I got an an iMac (27-inch, Late 2013) from my boss. Anyhow, it's really slow. I mean, it sometime takes 10 minutes to boot and opening app causes the computer to become unresponsive and the beachball appears. This probably intermitted. Sometimes the computer boot under a minute and everything act normally. Then it would suddenly become slow and unresponsive, then it would run normally again. Apple Diagnostic said "No issues found". Specs of iMac: 3.2 GHz Intel Core i5 8 GB DDR3 1 TB HDD NVIDIA GeForce GT 755M with 1GB GDDR5 UPDATE: I am going to be replacing the hard drive with a solid state drive. I will update this thread as things progresses. ...lot of photos, of cause! Let's hope that you like drama.