I'm a new (used) iMac owner and decided to upgrade the glacial 5400rpm HDD to a Samsung EVO 850 SSD. For anyone that's concerned about doing this themselves I can attest that it really isn't that hard. It took roughly an hour. The new models don't require a thermal sensor cable so it's a direct swap.
Some tips:
Some tips:
- Buy the pre-cut replacement adhesive strips. They are available form several retailers online and for <$10 on ebay. The fit perfectly.
- Buy the plastic cutting wheel tool. It's about $10 and makes screen removal very easy. Cut all around first (careful in the camera area) and use a guitar pick to loosen all sides.
- Follow the iFixit HDD upgrade and the adhesive strip guides.
- Take your time and be very careful with the screen cables. They're fairly robust but I'm sure they could be damaged easily.
- The hardest part for me was re-positioning the screen with the new adhesive - do a dry run with the liner still on the strips and make sure you have a feel for how the screen should line up. The adhesive is very strong so if you miss even a bit you may not be happy with the alignment. It might be worth buying an extra set of adhesive strips just in case you need to re-do it. I've heard that some people leave the original bottom strip on and just tilt up the screen but that didn't leave much room for my big clumsy hands.