Thank you for purchasing through links and ads on this site.
OWC / MacSales.com...
diglloyd Deal Finder...
Buy other stuff at Amazon.com...
Upgrade MacBook Pro Retina SSD
Internal SSD Wishlist…
Save big on Used Macs at OWC!
Mac Pro, Mac Mini, iMac, MacBook, MacBook Pro, iPad, Displays
Certified, and warranted by OWC
✓ Free shipping and 14-day money back guarantee

Thunderbolt vs USB3 Performance as RAID-0 Stripe

Last updated 2013-12-26 - Send Feedback
Related: Storage, USB, Thunderbolt, RAID
OWC Mercury Elite Pro Dual,
business end

See the overview of the OWC Mercury Elite Pro Dual.

To assess Thunderbolt vs USB3, a RAID-0 stripe configuration was used (double capacity, double speed vs a single drive metric).

A 1TB partition was made on the fastest 1/6 0f the drives (3 X 2TB = 6GB) in order to compare Thunderbolt to USB3 speed.

The drives were Toshiba 3TB, about as fast a hard drive as can be found, delivering peak speed of 170 to 180MB/sec on the very fastest side of the drive, hence the most that can be expected is 340 - 360 MB/sec in a dual-drive RAID-0 stripe.

Performance for many tasks revolves around sustained transfer speed (e.g. saving large Photoshop files). Anything requiring very high transaction rates (many small reads and writes) is better approached with a fast SSD.

Performance results

Both Thunderbolt and USB3 deliver to twice the speed of a single drive in a RAID-0 stripe configuration (very fast and as good as can be achieved).

       USB3: 355, 358 write/read MB/sec
Thunderbolt: 344, 356 write/read MB/sec

USB3 performs marginally better than Thunderbolt, discussion continues below.

Testing performed with the DiskTester fill-volume command. DiskTester is part of diglloydTools.

Sustained transfer speed MB/sec, DiskTester fill-volume for a 1TB partition
Mercury Elite Pro Dual with 2 X 3TB Toshiba HDD, Thunderbolt vs USB3

Comments

The Thunderbolt test was run twice; as shown this is the best-of-two runs (even a little more variation was seen with one run).

It turns out that USB is not only just as fast, but offers a slightly tighter performance envelope; the write speed variation with Thunderbolt is more (red line). In real world use, this is inconsequential.

Possible theory on Thunderbolt vs USB3 speed:

USB logic steps:
Drive > SATA to USB controller > USB cable > USB host/chipset

TB logic steps:
Drive > SATA to PCIe controller > TB controller > TB cable logic > cable > TB cable logic > TB Host controller

SSD Upgrade for MacBook Pro Retina
Internal SSD Wishlist…

diglloyd.com | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2008-2017 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__