Does anyone know how well one of these adapters performs? I want to connect a SATA SSD through a USB3 port but I'm afraid that an adapter will reduce the performance significantly...

Also is there a difference between cheaper and costlier adapters? For example $2 and $20?

  • What SSD make and model, exactly? They vary greatly in speed.
    – Daniel B
    Mar 31, 2016 at 5:28
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    It also matters if you have a USB3 to SATA convertor which supports USB attached SCSI protol.
    – Hennes
    Mar 31, 2016 at 5:48
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    I haven't chosen one yet, but I'm looking for something at around 400mb/s at least. It will be a model of 240-520GB, I don't care about any features as long as it's reliable and performs well. Also cheap.
    – Jack
    Apr 2, 2016 at 3:32

1 Answer 1


Not sure if it's the right place for your question (or for my answer) but I'll share what I've got.

I have two from IOCrest:

USB 3.1 Gen 2 (ASMedia ASM1351): http://www.amazon.com/IOCrest-Type-C-Controller-Adapter-SI-ADA20175/dp/B010U57FP2

USB 3.0 (JMicron JMS567): http://www.amazon.com/IO-Crest-Adapter-Drives-SI-ADA20155/dp/B00LPUV06C

I use both of them on a USB 3.0 port (Intel H87). UASP is supported by the host and the adapters. SSD is a Silicon Power S70 240GB (exactly the same one for both, I switch back and forth).

ASMedia ASM1351:

enter image description here

JMicron JMS567:

enter image description here

As you can see, the sequetial R/W wouldn't be much of a problem. But the random R/W performance can vary quite a lot. Apparently it is (partly?) because of the maximum number of streams/queues supported by the chip (queue_depth seen in Linux under UAS mode are '30' and '14' respectively).

Make sure you at least enable the write cache on the disk, like this:

enter image description here

Otherwise the performance will be something like this:

enter image description here

This is the same case with SATA as well.

In case this looks too much like an advertisement for IOCrest. I'll tell a bit about the ones from StarTech as well.

I got one USB 3.0 from StarTech. Not quite certain about the its chip. StarTech told that it's a ASMedia ASM1051E, but from what I can see in the system it could actually be an ASM1153 or ASM1153E: http://www.amazon.com/StarTech-SATA-Drive-Adapter-Cable/dp/B00HJZJI84/

I use it on an ancient (but sacredly decent) Intel X25-M 80GB 50nm:

enter image description here

As you can see, even when it's an older chip from ASMedia, but it still beats JMicron in the random performance. (It's slightly more expensive though, but that's generally true for the ones from StarTech.)

StarTech also provides USB 3.1 Gen 2 ones (Type-A and Type-C). They use the same chip (ASM1351) as the one from IOCrest. Although IOCrest provides its USB 3.1 Gen 2 one with an additional USB 3.0 Type-B to Type-C cable, but I don't think you can get the power supply that can be provided by a native Type-C cable from that. Instead, the ones from StarTech has non-detachable cables. Though I do not own one myself and hence never tested it on a 3.5" HDD or some power hungry SSDs, so I am not certain whether its Type-C one really performs better in terms of power supply.

Speaking of this, do NOT expect that all the SSDs would work with an adapter that is powered by a single USB 3.0 Type-A port.

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    Just make sure both your host and the adapter/external SSD you are going to buy support UASP, otherwise their random 4K QD32 performances are probably gonna be the same as its random 4K ones, which will be low as you can see.
    – Tom Yan
    Apr 2, 2016 at 9:52
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    The ASM1351 controller supports TRIM / UNMAP with the latest firmware update.
    – Monstieur
    Aug 22, 2016 at 7:08
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    @Locutus Yes. It appears to me that ASMedia (and JMicron) would release different "branches" of firmwares to the adapter vendors, and firmware with UNMAP->TRIM support (or some other feature) is only provided if the vendor specifically request for it.
    – Tom Yan
    Aug 24, 2016 at 10:07
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    @Locutus they are not the same. The actual versions of StarTech's firmware are 150708_B1_0A_01 (original in the adapter without UNMAP support) and 150708_B1_0A_02 (update on StarTech website with UNMAP support). The version can be revealed with the Mass Production Tool available in the SIIG zip archive (as well as the filename of the actual firmware file extracted to user's Temp folder).
    – Tom Yan
    Aug 24, 2016 at 12:29
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    @pacoverflow I did SATA vs USB benchmark of ASM1351 here - imgur.com/a/rcbTt Sep 25, 2017 at 18:27

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