[NewsPoster]

In a post today on its Rocket Yard blog, Other World Computing (OWC) announced a new in-line digital thermal sensor for owners who want to upgrade the hard drives in their iMacs. The sensor kits are compatible with models from 2009 all the way up to the latest 2014 Retina 5K model, allowing the use of third-party replacement hard drives (which the company conveniently sells), overcoming a troublesome proprietary issue on the machines.

While drive failure doing the useful life of most Macs is rare, a replacement of the drive can be difficult in some models. Until now, replacing the drive in one of the iMacs dependent on the hard drive temperature sensor required taking the machine to an Apple authorized service provider (AASP) or Apple Store, adding cost and bother. OWC is selling three versions of the kit, with or without an included tool box of necessary screwdrivers: one for 2009 and 2010 iMacs, one for the 2011 models, and one for the 2012 and later machines. All come with all the needed tools, and run between $57 and $59. A tool-free version is available for between $42.50 and $45.

The sensors are engineered to work natively with the diagnostics and System Management Controller in the compatible models. An OWC representative provided more information about how the in-line sensor helps overcome compatibility issues between higher capacity third-party hard drives and iMacs, with it basically coming down to the changes made year-to-year on the pin-outs or existence of thermal sensor pins.

The kits are sold separately from the hard drives, but they do come with a set of tools for installation, suction cups for screen removal, a microfiber cloth, and step by step instruction videos online. "The In-Line Digital Thermal Sensor DIY Kits for iMac embody OWC's commitment to DIY enthusiasts and upgraders everywhere," said Larry O'Connor, OWC's founder. "Our innovative kit is a complete solution that gives Mac users more options to upgrade their iMac's internal storage while retaining proper system operation."

[que_ball]

That's a good option. In the past I have simply installed a third party tool to control the fans as a result of a hard disk replacement.
Sounds a little pricey for the cable only part but nice to know it's available.

The article does not seem to spell it out but the problem with replacing the drive is that without a compatible temperature sensor built into the drive the fans start spinning at maximum speed. The computer works fine but max speed on the fan is very loud and likely not very good for the long term health of those fans either.

So up to now you could install a third party tool to either manually control the fan speed or to have it read the temperature from the SMART diagnostics on the drive and adjust speeds accordingly. That means this third party tool needs to always be running and set to start on bootup. You also have to replicate the solution for any other boot environments you may have. So booting from a USB or Bootcamp partition could be troublesome as your fans spin up to max again.