Having problems with 21.5" i3 2010 distorted blank/rainbow pixel screHi @mayer I am having a similar problem to what Sam reported. My iMac is an A1311 (EMC 2389) -- mid-2010 with 21.5"...
"Can SATA III HDD be installed on mid 2010 iMac Intel 21.5""に関する回答Correct answer is yes, a SATA III drive will work on a SATA II system like your iMac. See my comment above to @danj's answer.
"Can I replace iMac's harddrive with an SSD?"に関する回答@Dan - I've got a question about some of the information you've posted. Background: I have a mid-2011 21.5" iMac. In Disk Utility, the hard drive (factory-original Seagate ST3500418AS, 500GB) reports S.M.A.R.T. status as "failing." In researching how to properly replace the HD, I've seen all the discussion (here and elsewhere) about the proprietary temperature sensing firmware etc. that was added in the 2011 iMacs. In your comments above, you mention a couple times that replacing the factory HDD with a SSHD would not require the OWC in-line sensor cable ("get a SSHD that has the builtin sensor and gives you similar performance of a SSD" -- 1/6/2015; "the SSHD has the needed built-in thermal sensor (you won't need the OWC cable)" -- 1/6/2015). But then elsewhere, you say that even with an SSHD, you'll still need the OWC in-line sensor cable ("Don't forget you'll need the OWC in-line sensor if you go with the SSHD!" -- 9/16/2017; "You still need the OWC in-line thermal sensor cable." -- 9/16/2017). I'm not...