Can I use an external SSD as my main OS drive?

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Level 3

931 points

Can I use an external SSD as my main OS drive?

I have a 2013 iMac with an internal 1TB 5400 RMP drive. I've become spoiled with my macbook pro's SSD drive. I have considered replacing the internal drive with an SSD, but one, it is very expensive (including the labor), and two, if someday I get a new mac (this is my 5th iMac since they first came out), I'll have to pull it out, etc.

So I'm looking at the OWC Mercury Elite Pro mini 480GB SSDas an external option. My question is, can I run my iMac on the external drive? Has anyone out there done this? I realize it is much smaller than my current internal drive, but excluding data like iTunes library, pictures, etc., I am only using about 200GB for the OS and applications. I was thinking of installing the OS and applications on the SSD, and use the internal for data, etc., and maybe even setup a 500G partition to clone the SSD to it, as a backup option.

Any comments or suggestions?

Thanks

iMac, OS X El Capitan (10.11.5), 8GB RAM, 1TB HD

Posted on Jan 28, 2017 7:57 AM

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Answer 1

rkaufmann87

Level 10

148,546 points

Jan 28, 2017 8:02 AM in response to Alfredo Jahn

That would work but it would not provide the performance you want. You should get a Thunderbolt enclosure, install the SSD in that and then use that drive as your startup drive. The enclosure you selected while a fine one does not have a Thunderbolt port and Thunderbolt provides the best performance.

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Answer 2

Alfredo Jahn Author

Level 3

931 points

Jan 28, 2017 8:58 AM in response to rkaufmann87

rkaufmann87 wrote:

That would work but it would not provide the performance you want. You should get a Thunderbolt enclosure, install the SSD in that and then use that drive as your startup drive.

Yeah, I realize that Thunderbolt would be better, but I'm trying to keep the cost down if possible. Right now I have a 5400 RPM drive. I'm thinking USB 3 would be pretty good.

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Answer 3

rkaufmann87

Level 10

148,546 points

Jan 28, 2017 9:36 AM in response to Alfredo Jahn

Alfredo Jahn wrote:

rkaufmann87 wrote:

That would work but it would not provide the performance you want. You should get a Thunderbolt enclosure, install the SSD in that and then use that drive as your startup drive.

Yeah, I realize that Thunderbolt would be better, but I'm trying to keep the cost down if possible. Right now I have a 5400 RPM drive. I'm thinking USB 3 would be pretty good.

Okay, so yes the enclosure you chose will work. However IMHO I'd save up a few more $ and buy a Thunderbolt enclosure, the performance increase is worth it.

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Answer 4

padams35

Level 4

3,613 points

Jan 28, 2017 9:36 AM in response to Alfredo Jahn

USB 3 is pretty good and will provide the performance most users want. It peaks about 50% faster than a 7200 RPM drive for pure read/write speeds and should also capture the SSD low-latency advantage.

MacWorld article: http://www.macworld.com/article/2039427/how-fast-is-usb-3-0-really-.html

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Answer 5

Alfredo Jahn Author

Level 3

931 points

Jan 28, 2017 9:51 AM in response to padams35

padams35 wrote:

USB 3 is pretty good and will provide the performance most users want. It peaks about 50% faster than a 7200 RPM drive for pure read/write speeds and should also capture the SSD low-latency advantage.

MacWorld article: http://www.macworld.com/article/2039427/how-fast-is-usb-3-0-really-.html

WOW! Very interesting article. I currently have 2 external 2TB drives and run them using FireWire 800. They also have USB 3 connections. I may consider using the USB 3 instead... What I got from this article is that USB 3 is pretty much the same speed, if not even just a bit faster than Thunderbolt. I found that VERY SURPRISING.

Just continued reading the section on using an SSD and see that the Thunderbolt does a little better than the USB 3 but is it worth the extra money? Not sure.

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Answer 6

Jan 29, 2017 3:49 AM in response to Alfredo Jahn

I have a late 2013 27" iMac and have boot drives on external SSD's on both

Thunderbolt and USB3. My primary boot drive is connected via Thunderbolt

and my secondary is via USB3 (primary is Sierra and secondary is El Capitan).

Under normal use (web browsing, video viewing, etc.), I find that there is really no

discernible difference in performance. Boot time on the TB is faster, but both are so fast

(at least to me) that the difference is pretty much a non-issue.

Where I typically see a difference in use, is when using things like large code development

projects for microprocessors during compile cycles which create lots and lots of files and

is therefore highly disc intensive. Even at that, they are both really quick and heads above

any HDD.

So, unless you really, really want the absolute fastest possible external solution,

go USB3 and save your bucks for more back up storage.

If you really want super duper fast, multiple drives configured in a RAID array

enclosure on TB is the way to go.

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Answer 7

Alfredo Jahn Author

Level 3

931 points

Jan 29, 2017 7:35 AM in response to woodmeister50

woodmeister50 wrote:

So, unless you really, really want the absolute fastest possible external solution,

go USB3 and save your bucks for more back up storage.

Thank you for this post. It really helps. I do want to save some money, but.... The Transcend 512GB Thunderbolt is $297 with free shipping. The OWC Mercury Elite Pro USB 3 480G SSD is $269. That's a $28 difference. I'm thinking both would be the same speed? I don't own any TB drives, so it sounds like it would be fun to get one. :-)

When you talk about boot times, what are we talking? Have you timed it? My main computer is a Macbook Pro Retina, 13-inch, Late 2013 with 8G and SSD. It is lightning fast, as you can imagine. Going back to my iMac, even during normal times (when I am not experiencing slowdowns, which is a separate problem), Seems pretty slow, and boot times, forget about it, minutes.

Although I am a Java developer, I don't do any programming on my iMac. I do on my macbook, but we're covered there. I would also like to try Siera, so I guess an external boot works great for that.

One last question(s), what do you do with your internal drive? Do you ever boot from it? Is it mostly for data? Are there any issues using TimeMachine for backups when you have different OS drives?

Thanks again!

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Answer 8

Jan 30, 2017 4:01 AM in response to Alfredo Jahn

One last question(s), what do you do with your internal drive?

I use it as a clone of my primary external drive.

Do you ever boot from it?

Only occasionally to make sure my clone is functional.

Are there any issues using TimeMachine for backups when you have different OS drives?

Not a fan of Time Machine and prefer cloning as it can be

immediately booted should something go wrong as opposed

to what can be hours of downtime involved in restoring from a Time

Machine backup. I can then deal with the problem when I have the time.

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Answer 9

Alfredo Jahn Author

Level 3

931 points

Jan 30, 2017 4:39 AM in response to woodmeister50

woodmeister50 wrote:

One last question(s), what do you do with your internal drive?

I use it as a clone of my primary external drive.

Do you ever boot from it?

Only occasionally to make sure my clone is functional.

Are there any issues using TimeMachine for backups when you have different OS drives?

Not a fan of Time Machine and prefer cloning as it can be

immediately booted should something go wrong as opposed

to what can be hours of downtime involved in restoring from a Time

Machine backup. I can then deal with the problem when I have the time.

Sorry for all the questions... Do you use Carbon Copy Cloner to clone? Do you automate it to keep the clone updated nightly? My internal is a 1TB the SSD I'm looking at is half that size. Should I partition my internal with two partitions and clone to one and use the other for data?

Also, what brand/size external SSD do you have?

Thanks again.

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Answer 10

Feb 1, 2017 3:22 AM in response to Alfredo Jahn

I have been using Carbon Copy Cloner since version 1.0 and

it is a solid product. With my iMac, I pretty much do manual

updates weekly and as needed. Always before any system update

or updates/upgrades to any major apps. FWIW, I also keep seperate

and duplicate backups of all my data (WIP, photos, etc.). In my opinion,

data is the most important to backup and should be done to multiple

independent destinations. By doing separate backups of data daily,

I don't really need nor require daily clones since the base system

doesn't change on a daily basis (OS and apps).

I do have a MacMini that I use as a server and use Carbon Copy Cloner

on an automated weekly schedule (the Mini runs 24/7).

One thing about Carbon Copy Cloner is that the first clone does take a

while since it is backing up the entire drive. After that though, it can be

set up to do incremental clones, only modifying what changed, and can

also save the old stuff.

As far as SSD, I am currently using a Sandisk UltraII 960GB. Not the fastest

of SSD's but still a lot faster than an HDD and reasonably prices. It is currently

connected via Thunderbolt with one of the old Seagate "sleds". The other drive

is a 240GB Kingston SSDNow v300 in a Startech USB3 enclosure.

One last note. Personally, when it comes to data I believe you should have

as many backups and types of backups as you can afford. If you use your

computer or business, it is a requirement to have and budget such an expense.

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Answer 11

Alfredo Jahn Author

Level 3

931 points

Feb 1, 2017 4:38 AM in response to woodmeister50

Thanks again for your info. I too have been using CCC off and on for years. I use it for clones and for backing up folders, etc. What got me started down the SSD path was my iMac was running very slow. I think I found the problem. At least it is looking like one of my external OWC Mercury Elite Pro 2TB drives may be failing and that seems to be slowing me down. A few days ago I unmounted it and I have not seen any slow down issues since. I have a new one arriving tomorrow and plan to copy all the data off. I plan to reformat it and maybe us it for an extra back up, still looking for a good application for verifying if a disc is going out or bad...

Originally I also thought that the way I set the iMac up might be causing issues, since I did a migration from an older iMac running Snow Leopard. I have done some manual cleanup after running Etrecheck. Not sure if that was the fix or removing the external, which is making a lot of noise (seek noise).

I'm expecting a bonus this year at work, so I plan to pick up this Samsung T3 SSD 500G. What do you think about that drive? I currently have a 1TB internal, but only have around 350 used. I can always store my music and pictures on an other external. If the bonus is good, I may get the 1TB instead :-)

Thanks again for the help!

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Answer 12

Feb 2, 2017 3:22 AM in response to Alfredo Jahn

I don't have any experience with that drive so I really can't comment.

Personally, I have moved away from "manufacturer integrated" solutions

to purchasing reliable enclosures and making my own choice of the

drive stuffed in them.

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Answer 13

dwb

Level 7

33,298 points

Feb 2, 2017 6:51 AM in response to Alfredo Jahn

Like woodmeister50 I'm not a fan of what I call big box store external drives but I especially don't like WD externals. When I was looking at the same issue you are, I purchased a USB 3 external enclosure from OWC and an SSD. I prefer Crucial 's & OWC's drives these days. I tested both a USB 3 and Thunderbolt and while the Thunderbolt solution was faster I felt the USB 3 solution was fast enough and the extra cost didn't match the extra speed.

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Answer 14

Alfredo Jahn Author

Level 3

931 points

Feb 2, 2017 12:37 PM in response to dwb

dwb wrote:

Like woodmeister50 I'm not a fan of what I call big box store external drives but I especially don't like WD externals. When I was looking at the same issue you are, I purchased a USB 3 external enclosure from OWC and an SSD. I prefer Crucial 's & OWC's drives these days. I tested both a USB 3 and Thunderbolt and while the Thunderbolt solution was faster I felt the USB 3 solution was fast enough and the extra cost didn't match the extra speed.

I pretty much ONLY use OWC external drives. I own 5 of them at the moment (2 on my iMac, and 3 on my son't mac mini). One of my 2TBs is no the fritz and will be replaced tonight with a new OWC Mercury Elite Pro USB 3. I have been considering maybe getting the OWC Mercury Elite Pro mini and a Samsung 850 Evo to slap in it. I have read several articles about different enclosures not being as fast as others. I have always used firewire with my OWC externals. The most recent purchase (arriving today) is a USB 3.0. I figured with the speed it offers, why pay extra for firewire?

I guess I an talk to OWC about the speed of their enclosures. I hear the Samsug 850 Evo is a fast SSD.

Comments? Suggestions?

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Answer 15

dwb

Level 7

33,298 points

Feb 2, 2017 12:49 PM in response to Alfredo Jahn

I Have that OWC enclosure with a Crucial drive installed. I have several Samsung drives and that's one of the lines we carried where I used to work. But I became unhappy with their tech support two years ago and felt they were bouncing me around instead of addressing a big problem. Crucial was running a sale at the time so I grabbed one and returned my third not working Samsung SSD. So crucial and OWC for me.

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