SMALL RANDOM TRANSFER TEST
We used a range of 4K to 1024K blocks in the Standard Random test of QuickBench as a predictor boot volume 'house keeping' performance and a simulation of an application that does multiple small random transfers.
Again, RED graph bar means the fastest overall. ORANGE bar means the fastest SINGLE drive enclosure.
The performance of bus-powered Thunderbolt drives has indeed improved since we tested the original Thunderbolt SSD from Elgato which topped out at 271MB/s.
The Akitio Palm RAID (6.8 ounces w/cable; 4.72 x 3.11 x .55 inches) is a bus-powered Thunderbolt RAID enclosure that uses dual flash modules. Consequently it tested faster than all the single drive Thunderbolt bus-powered samples. It includes an integrated Thunderbolt cable. The 4 inch length works fine with a laptop but is one inch too short for Mac desktops. The Palm RAID 'dangles' instead of laying flat when connected to the 2013 Mac Pro or 2013 iMac.
The Other World Computing Mercury On-The-Go Pro 11.2 ounces w/cable and SSD; 5.5 x 3.5 x 1.0 inches) is a bus-powered Thunderbolt enclosure ships with a 1TB WD10JPVX HDD. We pulled it out and replaced it with OWC's own Mercury Extreme Pro 6Gbps SSD (240G). Our apologies for overlooking this option in the initial posting. Turns out, it's the best performing SINGLE drive bus-powered Thunderbolt enclosure overall. CAVEAT: If you open the case to replace the HDD with an SSD (including OWC's), the warranty is voided. Hopefully OWC will seen offer a certified SSD version that is covered under warranty.
The LaCie Rugged Thunderbolt (10.0 ounces w/cable; 5.5 x 3.5 x 1.0 inches) not only comes with an integrated 'pull out' 14 inch Thunderbolt cable but includes a USB 3.0 port (and cable). That gives it maximum flexibility when moving data from new Mac to old Mac and back. It also comes with a utility for easy creation of a Windows compatible partition for sharing data with Windows PCs.
The Elgato Thunderbolt Drive + (9.2 ounces w/cable; 5.2 x 3.3 x 0.8 inches) performed on par with the other bus-powered enclosures with SSDs. As with the Rugged, it adds the flexibility of a USB 3.0 port. Cables for both Thunderbolt and USB 3.0 are included.
The Seagate GoFlex Thunderbolt Adapter (7.2 ounces with SSD + cable; 4.75 x 2.9 x 1.0 inches) is useful as a SATA-to-Thunderbolt notebook drive dock. That's handy if you do a lot of drive switching. The main caveat is that when it comes to SSDs, only asynchronous models like the TransIntl SwiftData Async and the OWC Mercury Electra will work reliably. Synchronous SSDs like the Mercury Extreme or Samsung 840 Pro either refuse to mount or dismount unexpectedly. Seagate prefers to sell you the adapter bundled with their custom 1TB HDD module, but you can buy just the adapter on Amazon.
The Akitio Neutrino Thunderbolt Edition (9.3 ounces w/cable; 5.1 x 3.1 x 1.0 inches) had the FASTEST large sequential READ speed of the single drive SSD enclosures yet the SLOWEST small random WRITE speed.
The Western Digital My Passport Pro is a dual drive RAID like the Palm RAID but instead uses dual HDDs of either 2TB or 4TB aggregate capacity. What it lacks in speed is made up in capacity. It's the heftiest of the bunch at 1.1 pounds w/cable, 5.6 x 3.5 x 1.3 inches for the 2TB model and 1.6 pounds w/cable, 5.6 x 3.5 x 1.7 inches for the 4TB model.
Just for fun we striped three different bus-powered TB drives and plugged them into three separate TB ports on different TB busses of the 2013 Mac Pro. That 'mutant' RAID set topped 1000MB/s. Product idea? Or just mad science?
COMING SOON: comparison of the latest bus-powered USB 3.0 drives -- some of which do large sequential transfers faster than the bus-powered Thunderbolt drives!
THUNDERBOLT BUS-POWERED PRICE LIST
Akitio Palm RAID 512G = $649.99 (direct or from Amazon)
Akitio Neutrino TB 256G = $339.99; 512G = $569.99 (direct or from Amazon)
LaCie Rugged TB SSD 250G = $299.99; 500G = $499.99
LaCie Rugged TB HDD 1TB = $219.99; 2TB = $299.99
Elgato Thunderbolt Drive+ 256G = 499.95 (Amazon $434.99); 512G = $899.95 (Amazon $779.99)
Seagate GoFlex TB Adapter (no drive) $99.99 (Amazon $80.99) + 240G SwiftData Async SSD $124 (TransIntl.com) = $204.99; See also Mercury Electra 240G Async (OWC) and GoFlex TB 'Backup' 1TB HDD bundle = $229.99 (Amazon $139.99)
WDC My Pasport Pro 2TB HDD RAID = $299.99 (Amazon $293.99); 4TB HDD RAID = $429.99 (Amazon $420)