USB 3.0 speed testing

Hi all,

Over the last few weeks, I’ve been speed testing USB 3.0 as an alternative to eSATA. I’ve got some results to report!

For spinning media, USB 3.0 is basically as fast as SATA. I tested several 2.5″ laptop drives from 5400RPM and 7200RPM for sustained writes, and the USB 3.0 caddy added no significant overhead. Here are the results:

Seagate 320GB 7200RPM: SATA – 291GB/hr, USB 3.0 – 288GB/hr
Hitachi 320GB 5400RPM: SATA – 272GB/hr, USB 3.0 – 272GB/hr
Hitachi 500GB 5400RPM: SATA – 303GB/hr, USB 3.0 – 302GB/hr

As most people will be backing up to spinning hard disks, I can conclude that USB 3.0 is as good as eSATA.

However, for SSDs, the story is different. USB 3.0 seems to bottleneck:

Kingston 128GB SSD: SATA – 793 GB/hr, USB 3.0 – 350GB/hr
G.Skill Falcon 128GB SSD: SATA – 479GB/hr, USB 3.0 – 200GB/hr

I find it weird how USB3.0 doesn’t just cap the transfer rate, but degraded the G.Skill’s transfer rate.

I also have a Patriot SSD that I haven’t yet tested, so I look forward to doing that and seeing if the results alter.

Conclusion: USB 3.0 is great for spinning media. Weird for SSDs. I need to investigate more.

Have a great weekend all!


6 thoughts on “USB 3.0 speed testing”

  1. One less test we need to run in our labs, THANKS Linus!

    One other thing I’d point out regarding SSD media, the transfer speeds REALLY depend on if the drive was formated to all 0’s before speed testing.


  2. If the SSD is new, you might see faster results than when you do it a second time because of the time it takes to recover sectors that have been erased. Did you take any special steps to prepare the drive before writing to it? A standard windows format or delete will not do it unless you are running under an OS that supports Trim and you give it time to recover.

  3. That’s nice testing Linus, thanks.

    What USB3 cards do you recommend for existing servers? We have tried a few but sometimes the drives for Windows Server are not very good.

    It amazes me that the likes of Dell still do not have a USB3 card.

  4. I installed a usb 3.0 port and an external usb 3.0 HD. My computer was a top of the line dell only 1 year old. Yet it seems to be no faster than usb 2.0 . Does anyone know if there is actual software for the layman to test out and make sure everything is running ok? Thanks

  5. Your tests are useful for large transfers, but fail to test where there is a big difference due to latency.

    Tests with many smaller writes generally show USB 3.0 latency to cause significant performance degradation vs. eSATA.


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