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iMac external Thunderbolt SSD drive solution


Judging by the readership of my posts on iMacs and SSDs, there is tremendous interest in upgrading the Mac desktop computers to SSD. Many, including me, have regretted not stumping up the extra for the twin-disk configuration at the outset.

Unfortunately, adding an additional internal SSD to an iMac is extremely difficult because of the lack of brackets. Even replacing the standard HDD with an SSD is not for the timid because of the difficulty of removing the screen and getting inside.

Cowardly custards like me have opted for the much simpler alternative of adding an external SSD boot drive. If you have an iMac with a Thunderbolt port this is an excellent and viable solution. I would not recommend it if you have only FireWire or USB at your disposal.

Lacie Little Big Disk

Last March I explained how I had added a 240GB LaCie Little Big Thunderbolt drive to my 2011 27in iMac. Right from the start it boosted access speeds to nearly 500 Mb/s, a massive increase on the standard internal HDD. It continues to work faultlessly, although the main problem, as I mentioned in the original article, is noise. This is one noisy little beast. It is a mains powered device and seems to need a mighty powerful fan.

Seagate Thunderbolt adaptor

A couple of months ago I told you I had bought a 1TB Seagate GoFlex drive and the matching Thunderbolt adaptor. Although the drive is a 7,200 rpm mechanical device, I realise that the eSATA socket on the Seagate adaptor might fit any 2.5in internal drive. I experimented with an old 256GB SSD and, sure enough, it works well. This, then, is an alternative to the LaCie. Not only is it cheaper, it has the advantage of being one discrete unit (the LaCie housing contains two linked 120GB drives) and is bus powered, hence no noisy fan.

My friend Paul Gauntlett, whose experience of installing a 480GB OWC SSD in his MacBook Air I covered in the last article, read my earlier description and decided to have a go with the external Seagate solution:

For the iMac 27 inch I put a Crucial M4 256gb into the Seagate Thunderbolt enclosure to use as my boot drive and again used CCC to clone across, including the recovery partition. It is so much faster (and quieter) than booting off the internal HD which – like you – was frustrating me no end. It is also much more responsive in operation. I have used double sided (No Nails) tape to secure the Seagate enclosure to the back of the iMac stand so that it, the SSD and the Thunderbolt cable are out of sight against the wall and away from prying grandchildren’s hands.

Best solution

Paul’s solution, which obviously works well, is better than my choice of the LaCie. Not only is it silent and out of sight, it can accept FileVault 2 activation because it is a single drive, unlike the LaCie. It is also cheaper, even taking into account the Seagate Thunderbolt adaptor.

by Mike Evans, 1 September 2012