Ask Different is a question and answer site for power users of Apple hardware and software. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have a 2011 iMac 27", and back then opted for a HDD. Back then (and now still) I fear for the lifespan of SSDs, and hauling an iMac 27" to the store is cumbersome, so it looked the right choice.

But now, I notice that the drive is the main bottleneck for pretty much anything I try to do, and I would love to benefit from the better performance of an SSD. (Though still not regretting my choice for HDD internal storage, mind.)

Will installing OS X and my applications on an external SSD be faster than an internal HDD?

If I did my reading right, I really should be getting something with a Thunderbolt connection. But I wanted to check here to be sure, and wondered if OS X is at all bootable from a Thunderbolt drive?

share|improve this question
I guess if you chose the SSD as your initial mounting drive then I guess. I would do this and then have all my files on the internet HD – Phorce Jan 25 '13 at 18:14
up vote 2 down vote accepted

To answer your first question, Yes booting from an external SSD should be much faster than a stock HD.

Thunderbolt is definitely the fastest interface around so that shouldn't be the bottle neck.

Yes, from a brief Google search it looks like people are booting from Thunderbolt drives without a problem.

share|improve this answer

I own a Lacie Rugged SSD USB3/Thunderbolt 128 GB drive.

I am using it as a boot drive for my 2011 iMac over Thunderbolt.

I had no issues with it, I put the iMac into sleep over night. The drive never disconnected when a I woke up the machine from sleep. Although the drive is not as fast as an internal drive but it is a good option for an iMac if you do not want to install an internal SSD into an iMac.

This option is a lot faster than the internal 7200 rpm HDD. The apps load very fast. Before that I had a lot of problems with a lot of apps opened especially when I ran out of RAM. But I have no problems now using the SSD.

Some reported that you can not enable TRIM on an external SSD. I enabled TRIM with TRIM Enabler.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.