iMac external SSD boot drive

snapdragonx

macrumors regular
Original poster
Oct 31, 2012
141
1
Hi all,

Basically I'm wanting to setup an external SSD boot drive (via Thunderbolt or USB 3.0) on a late 2013 iMac (which I've yet to purchase).

Will this result in a loss of performance over an internal SSD?

Thanks for any info
 

yjchua95

macrumors 604
Apr 23, 2011
6,725
230
GVA, KUL, MEL (current), ZQN
Hi all,

Basically I'm wanting to setup an external SSD boot drive (via Thunderbolt or USB 3.0) on a late 2013 iMac (which I've yet to purchase).

Will this result in a loss of performance over an internal SSD?

Thanks for any info
In real world usage, no, unless you do heavy video editing or a benchmarker like me.

I have a Samsung 840 Pro 256GB in a Buffalo HD-PATU3 Thunderbolt enclosure and got 400MB/s in both directions.

The internal SSD in my iMac performs at 750MB/s in reads and 720MB/s in writes.
 

snapdragonx

macrumors regular
Original poster
Oct 31, 2012
141
1
In real world usage, no, unless you do heavy video editing or a benchmarker like me.

I have a Samsung 840 Pro 256GB in a Buffalo HD-PATU3 Thunderbolt enclosure and got 400MB/s in both directions.

The internal SSD in my iMac performs at 750MB/s in reads and 720MB/s in writes.
Interesting. The main use of the computer is video editing BUT I use an external RAID 0 as my media drive so the speed of the SSD is fairly irrelevant for that purpose.

I'm basically just wondering if it's worth the extra ~$250 to buy an internal SSD for the iMac, when I already have one lying around that I could put in an enclosure and use instead.
 

yjchua95

macrumors 604
Apr 23, 2011
6,725
230
GVA, KUL, MEL (current), ZQN
Interesting. The main use of the computer is video editing BUT I use an external RAID 0 as my media drive so the speed of the SSD is fairly irrelevant for that purpose.

I'm basically just wondering if it's worth the extra ~$250 to buy an internal SSD for the iMac, when I already have one lying around that I could put in an enclosure and use instead.
It's worth it, because the performance increase is quite significant in video editing.

Your external SSD in an enclosure would probably clock in at around 400MB/s, but an internal 512GB SSD in an iMac would perform at around 750MB/s in reads and 720MB/s in writes. For a 256GB, you'll get 720MB/s in reads and 660MB/s in writes (Samsung 256GB), and about 540MB/s in writes if you got a SanDisk 256GB instead.

If you buy a 256GB SSD, you're playing with the Samsung-SanDisk lottery.

For 512GB and 1TB, Samsung is the sole supplier.
 

Fishrrman

macrumors P6
Feb 20, 2009
17,449
5,665
If you already have a "bare" SSD on-hand, spend just $30 (or less) and put it into a USB3 external enclosure, or a USB3/SATA docking station.

I'll reckon the speed (provided you choose the RIGHT enclosure or dock) will leave you fully satisfied.

Aside:
You want an enclosure or dock with an ASMedia controller chip, and it should EXPLICITLY SAY that it supports "UASP" (USB Attached SCSI Protocol)...
 

DerekS

macrumors 6502
Jun 25, 2007
336
3
I boot/run from an external Lacie SSD Thunderbolt drive and it's substantially faster than the internal Fusion drive. Very happy with this setup.
 

SaSaSushi

macrumors 601
Aug 8, 2007
4,084
479
Takamatsu, Japan
I am doing just that, booting from an external Thunderbolt SSD. See here for a mini-review I did of the $18 Inateck UASP USB3 enclosure. I also compared it to the Delock 42490 Thunderbolt (about $100) enclosure I'm using.

The reason I went with the Thunderbolt enclosure, although it is very slightly slower, is the ability to enable TRIM support.

I see no performance difference from when I was initially booting to the iMac's Fusion drive. If you've already got the SSD, you may as well save your money, pop it into an enclosure and use it. :)
 

Blue Sun

macrumors 6502a
Feb 11, 2009
909
190
Australia
I boot/run from an external Lacie SSD Thunderbolt drive and it's substantially faster than the internal Fusion drive. Very happy with this setup.
Which Lacie external SSD do you have?

Also, does anyone know what make/model of SSD Lacie use in their products (Samsung 840 EVO, SanDisk etc.)?
 

hfg

macrumors 68040
Dec 1, 2006
3,566
277
Cedar Rapids, IA. USA
Which Lacie external SSD do you have?

Also, does anyone know what make/model of SSD Lacie use in their products (Samsung 840 EVO, SanDisk etc.)?
I have a 256GB LaCie "Rugged" Thunderbolt/USB3.0 which came with a SanDisk SSD in it. I just got a 500GB "Rugged" which has a 840 EVO in it.
 
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Blue Sun

macrumors 6502a
Feb 11, 2009
909
190
Australia
I have a 256GB LaCie "Rugged" Thunderbolt/USB3.0 which came with a SanDisk SSD in it. I just got a 512GB "Rugged" which has a 840 EVO in it.
Thanks for the reply. It is interesting that the rugged carries a 512GB Samsung 840 EVO. I've only ever seen the EVO series in the 500GB variety (i.e not 512GB).

Is there anyway to receive a Samsung drive rather than SanDisk?
 

Blue Sun

macrumors 6502a
Feb 11, 2009
909
190
Australia
Here is a DiskSpeedTest comparison (not the best for small random file access):

LaCie Rugged 256GB (SanDisk U100) ---------- LaCie Rugged 500GB (Samsung 840 EVO)
Wow, thank you very much for that. Much appreciated!

I am thinking about purchasing the Lacie rugged 256GB SSD to use as a Thunderbolt boot drive. Judging by those speeds - I think it should do nicely.

Thanks again.