Here's my upgrade experience to save others troubleshooting time: Procedure: Adding a Samsung 830 SSD to a 11,3iMac (27" mid 2010) without replacing the DVD superdrive. I went the OWC upgrade kit route. After following the video instructions however, all fans in my iMac ran full rpm. Running AHT ("d" at startup) gave me error code 4SNS/1/C0000008:TS2P--124 which means skin (i.e. case) temperature malfunction on the logic board. Disconnecting the SSD eliminated the error, so I knew it was the SSD and not the sensor, connector or some discharge damage. The solution was to swap the SATA connectors of the stock hard drive and the SSD on the logic board end, contrary to what the OWC video shows. After doing this everything works perfectly without any need for fan control. The procedure is imho not more difficult than replacing the superdrive with an SSD, so for those not going for a 3 hard drive setup I would recommend going this route instead of tossing out the superdrive.