# What is the speed of an external ssd when plugged into usb 2.0 port?



## boromaill (Jul 30, 2017)

Iam using several usb keys to transfer movies and stuff from one to another pc but it takes forever to transfer for example one 10 gb movie. Will buying an external ssd solve my problem. I see that its connected with pc via usb cable. What speeds will I be able to achieve? On one pc I have only usb 2.0 ports and on the other one I have usb 3.0 ports.


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## vega22 (Jul 30, 2017)

20mb/s give or take on usb2.

not able to network the machines?


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## qubit (Jul 30, 2017)

Yup, it would top out at the speed of the USB 2.0 connection, so would still be quite slow for an SSD.


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## TheLostSwede (Jul 30, 2017)

It can do a bit better than 20MB/s, maybe 40-45MB/s, but it depends on the USB to SATA adapter you use, or rather the chipset inside, as they don't all perform the same.
I'd still get a USB 3.0 based USB to SATA adapter with NCQ (Native Command Queuing), as it'll give you better behaviour on the USB 3.0, especially if you copy multiple files at the same time and add things over time.


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## vega22 (Jul 30, 2017)

yeah, i think the max theoretical is 60mb/s on usb2 but you never get near that in the real world :|


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## TheLostSwede (Jul 30, 2017)

vega22 said:


> yeah, i think the max theoretical is 60mb/s on usb2 but you never get near that in the real world :|



I hope you mean 60MB/s, mb/s would be milibits per second... Sorry to be pedantic, but it really matters.

Otherwise you're correct.


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## taz420nj (Aug 6, 2017)

If these are desktop machines, get an enclosure with eSATA, and install eSATA port brackets on both machines.  Then you are not limited to speed of the USB-SATA bridge, it is connected directly to the SATA interface..  Make sure in your BIOS that the SATA mode is set to AHCI - that way you can hot plug them.  If it is ATA, DO NOT change it, otherwise Windows will likely not boot until you do some registry hacking.

If laptop(s) are involved, get a SSD adapter for your optical bay.  Again, it's plugging directly into SATA without having to go through a USB bridge - and will have much higher throughput.  Laptops are odd though, you may or may not be able to select ATA/AHCI mode (especially with regard to the optical bay) so hot swapping/hot plugging may not be an option - you may need to power down to swap.


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## OneMoar (Aug 6, 2017)

10 or 15 MB/s depending on buss load/chipset
most cheap USB drives top out at 5 to 8MB/s write tho
id buy a USB3.0 card or a use a ESATA adapter


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## silentbogo (Aug 6, 2017)

boromaill said:


> Iam using several usb keys to transfer movies and stuff from one to another pc but it takes forever to transfer for example one 10 gb movie. Will buying an external ssd solve my problem. I see that its connected with pc via usb cable. What speeds will I be able to achieve? On one pc I have only usb 2.0 ports and on the other one I have usb 3.0 ports.


Definitely not on USB2.0. Even some USB3.0 enclosures don't live up to expectations.
If you want fast transfer speeds, then you should get a fast USB3.0 PCIe card and a newer enclosure - preferably based on ASM1153E controller, which supports SATA-III.
Not too long ago I bought a SiliconPower enclosure based on AsMedia ASM1153 (no E at the end, which is SATA-II only), and while it's cheap and works as expected, it's nowhere near the max potential of SATA-II interface (barely getting 150MB/s sequential R/W on Sandisk Ultra II).

Here's what I recommend:
- *Rosewill RC-508 4-port controller*. It's based on decent Renesas(NEC) controller. Not the fastest one on the market, but it should work out of the box, even for boot drives and KB/Mouse.
- *Zotac USB3.0 to SATA-III adapter*.  Based on ASM1153E. You can get any other enclosure or adapter, but make sure that it supports SATA-III.

Combined together, these two things will provide some decent performance, but at a cost. If you simply want the cheapest option, get a 2-port card and ASM1153 enclosure (can be as cheap as $20 for both).


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