Mac USB3 performance: worth the cost?

Now that some new Macs support USB 3.0, is the flexibility worth it? I test a USB3 to eSATA interface to find out.

The newest Ivy Bridge MacBook Airs and MacBook Pro include USB 3.0 that operate at a nominal 5Gb/sec along with 1 or 2 Thunderbolt ports with a 40Gb/sec cross-sectional bandwidth. That's incredible total bandwidth even before adding in the 6Gb/sec for the internal SATA SSD.

I own 5 eSATA and no USB 3.0 drives, so I checked to see if there were any USB 3.0 to eSATA adapters. The Bytecc adapters had higher user ratings and a lower price than the Belkins, so I bought several to test.

Test philosophy
My test approach differs from the dedicated hardware sites like Tom's and Anandtech. I look for obvious improvement - improvement you can feel - and assuming that, then look at the value: is the improvement worth the cost?

I don't worry about stopwatch timings or specs. Either I see a difference or I don't.

Test setup
A new MacBook Air with 2GHz i7, 8GB RAM and 500GB SSD connected to a Uspeed USB 3.0 7 port hub with a single Bytecc SuperSpeed USB 3.0 to eSATA 3Gbs adapter plugged in, connected to a half-full PopDrive with 2 mirrored 2.5" drives. Then I ran the Blackmagic Disk Speed Test app (BDST) - which is designed to tell video editors how many video streams a device can support - as the benchmark program.

To set the bar, I first ran BDST on the MacBook Air's SSD.

Screen Shot 2012-07-03 at 5.15.24 AM


Then I ran BDST on the PopDrive connected using its USB 2.0 port.

Screen Shot 2012-07-01 at 11.23.10 AM

BDST measured USB 2.0 performance was lower than expected. Previous experience with this drive - and in a year and a half of use, it has been flawless - has been in the 20MB/s range. But this is what BDST found, which may reflect the special requirements of dropped-frame-sensitive video.

Finally, here's the BDST results for the Bytecc eSATA adapter.

Screen Shot 2012-07-01 at 11.19.20 AM

The Storage Bits take
Is USB 3.0 on the Mac worth it? I have 3 answers:

  1. No. The 10Gb/s of USB 3.0 pales beside the 40Gb/s cross-sectional bandwidth of Thunderbolt.
  2. Maybe. That 7 port USB 3.0 hub cost $50. Each eSATA adapter is ≈$18 or $126 to fill the hub. And the eSATA cables are another ≈$40. Spend over $200 to get eSATA connectivity? Only worth it if you, like me, have several eSATA storage devices.
  3. Yes. The convenience of USB 3.0 is undeniable. The performance is significantly better than USB 2.0. And we can expect many more options for 3.0 than Thunderbolt is ever likely to have.

"Maybe" and "yes" win the day for me. But for many Mac users I suspect the answer will be "no" because they don't need anything more than Wi-Fi and USB 2.0 peripherals, let alone Thunderbolt.

If you do decide to start using USB 3.0 with your new Mac, take a moment to read this Apple tech note on USB 3.0. There are some USB 3.0 quirks you'll want to know.

Comments welcome, of course. I bought the MacBook Air, 3.0 hub and Bytecc adapters myself. I won the PopDrive at the 2011 CES.


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