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Any reason for an external USB 3.0 SSD?

kdoug

kdoug

macrumors 65816
Original poster
Jun 2, 2010
1,025
195
Iowa City, IA USA
Waiting for my rMBP and somebody mentioned installing an SSD in external USB 3.0 enclosure. Are there any speed advantages or are you bottlenecked with USB?
 
kdoug said:
Waiting for my rMBP and somebody mentioned installing an SSD in external USB 3.0 enclosure. Are there any speed advantages or are you bottlenecked with USB?
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The USB will be the biggest bottleneck, but it will still be quite fast for you. I doubt you'll be disappointed.
 
With USB 3.0 I'd think that yes the USB bottleneck you but you would notice a pretty significant difference between a HDD and a SSD, even in an enclosure.
 
USB 3.0 should have sufficient bandwidth for most SSD's out there and this is something I am planning on doing to get a Samsung 830 for around 150 and a USB 3 enclosure for around 30 which is not much more than a thunderbolt caddy and cable.
 
SandboxGeneral said:
The USB will be the biggest bottleneck, but it will still be quite fast for you. I doubt you'll be disappointed.
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You are wrong. USB is rated at 5 Gigabits per second which turn out to be 640 MegaBYTES per second. Taking into account real world numbers, lets say those 640 MB/s turn out to be around 540 MB/s.
Now, a good consumer SSD such as Crucial's M4, Samsung's 830, Vertex many drives, Sandisk new ones and Intel's 530 read speeds lie around the 500 MB/s mark (write speeds vary depending on drive capacity, but are generally slower than read speeds) and so, the USB3 port is NOT a bottleneck in this specific case (SSD's 500 MB/s vs USB3's real world 540 MB/s).

If you get a good USB3 enclosure and a good SSD, you're good to go.
 
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ACiB said:
You are wrong. USB is rated at 5 Gigabits per second which turn to be 640 MegaBYTES per second, taking into account real world numbers, lets say those 640 MB/s turn out to be around 540 MB/s. Now, a good consumer SSD such as Crucial's M4, Samsung's 830, Vertex many drives, Sandisk new ones and Intel's 530 read speeds lie around the 500 MB/s mark (write speeds vary depending on drive capacity, but are generally slower than read speeds) and so, the USB3 port is NOT a bottleneck in this specific case. If you get a good USB3 enclosure and a good SSD, you're good to go.
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This is the answer I was looking for. Any recommendations on a SATA III enclosure?
 
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kdoug said:
Best Buy, my Amazon showroom. :D
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And they, just like circuit city, will go out of business before admitting they are doing it wrong!

A little customer service goes a long way...but when I walk in and get ignored the whole time I'm there then when I finally approach someone to ask where something is and they have no clue, so I have to find it myself to find its 4x as much as on Amazon, you are doing something wrong.
 
kdoug said:
This is the answer I was looking for. Any recommendations on a SATA III enclosure?
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I don't own any enclosures, but when buying hardware I've found a good thing to do is browse newegg.com search for what I'm looking and then filter by rating, and read some reviews. Hope that helps!
 
ACiB said:
You are wrong. USB is rated at 5 Gigabits per second which turn out to be 640 MegaBYTES per second. Taking into account real world numbers, lets say those 640 MB/s turn out to be around 540 MB/s.
Click to expand...

The real world numbers are more like 250MB/s

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Hellhammer said:
The real world numbers are more like 250MB/s

Image
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You do understand that's a max speed by the hard drive and/or the external case itself, not the USB 3 limit?

Anand didn't say which drive he used. Also, he said this:

" (with all of my focus on Thunderbolt I actually don't have a 6Gbps UASP enabled USB 3.0 dock in house)"

So he hasn't even tried the faster USB 3.0 drive yet.

Also, barefeats shared a couple of benchmarks as well: http://www.barefeats.com/hard154.html

You can see there are some differences between USB 3.0 docks.

Hopefully, with UASP USB 3.0 docks, it should be able to go faster than 250MBps.
 
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daleski75 said:
Not sure thunderbolt for the extra outlay would add any benefits though.
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if I pop my SATA III Vertex 3 SSD in a USB 3.0 enclosure that says its a SATA III enclosure I get about 100MB/s real world speed.

Same drive with the seagate thunderbolt adapter I get 250MB/s read and write.
 
You are wrong. USB is rated at 5 Gigabits per second which turn to be 640 MegaBYTES per second, taking into account real world numbers, lets say those 640 MB/s turn out to be around 540 MB/s.
Click to expand...


LOL - USB3 will never see anything close to it's theoretical max, same as USB 2.0 never hit it's 400Mbps. Just trust me on that. FWIW, USB2 typically maxes out around 25MBps, or 200Mbps. Firewire 800 used to be the best option on MBP's, but now we have thunderbolt.


OP: If you are spending the $$ on a SSD, you might consider using it with Seagates Thunderbolt goflex adapter. (Remove the magnetic drive and replacing it with the ssd - there are youtube videos on how to do this.) Tests have shown it is (not surprisingly) way faster than USB3. This is what I intend to do with my 480GB Intel 520, that is sitting my now unused MBP17.
 
Don't want to hijack this thread but my question is related to the discussion so far.
If I'm not using an SSD but instead just using a regular Seagate Go Flex 2.5" 5400 drive over USB3, I would assume that hooking that same drive to the Seagate TB adaptor would show no real benefit?? Is it correct to say that you need an SSD in order to see any speed benefits when comparing USB3 to TB? Even a 7200RPM drive wouldn't benefit from TB would it?

Thanks.
 
arbitrage said:
Is it correct to say that you need an SSD in order to see any speed benefits when comparing USB3 to TB? Even a 7200RPM drive wouldn't benefit from TB would it?

Thanks.
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Right.

Technically, under very very intense benchmarking the lower latency of thunderbolt might show an extremely tiny improvement, but this would be impossible to notice by any human. ;)

If your not running an SSD externally don't bother with the thunderbolt adaptor... Unless you want to free up a USB port.

BTW, for anyone that is interested, here is a comparison of USB3 vs Thunderbolt vs SATA. Although I doubt the USB3.0 implementation they are using is the fastest around. (And the same holds true for their Thunderbolt implementation.)
 
kdoug said:
This OWC Elite Pro Mini seems to be one of the best 3.0 enclosures according to Barefeats.
http://eshop.macsales.com/item/Other World Computing/MEPMU3ES/
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I have one (OWC enclosure from eBay). I like it a lot. I tested my Samsung 830 512gb in it after doing a HDD to SSD clone and as hellhammer said 250 MB/s was what I was getting as well using black magic to test the connection. Obviously when I put it into my mbp the sped was almost double.
 
I'm doing exactly this and have not found a SATA III USB 3 enclosure at all (in the UK) for the samsung 830 256GB SSD i have in my old 2010 13" MBP.

I've settled (for now) on an icybox enclosure that is SATA II. ~250Mbps will be sufficient for holding a lightroom library and other bits and bobs.

Seems like we'll have to wait :(
 
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