Originally posted Saturday, March 23rd, 2013, by rob-ART morgan, mad scientist

What prompted this article was the announcement this week that the FirmTek miniSwap/U3 is shipping. You might recall our review of it back in January where it impressed us with new found USB 3.0 speed. How does a USB 3.0 bus powered notebook size storage like the miniSwap/U3 compare to Thunderbolt bus powered notebook size storage devices?

Other than performance, what features distinguish them? But since we at Bare Feats Test Lab are all about performance, that's where we will start. To squeeze the most out of each device, each was equipped with an SSD -- and where possible, one or more 6Gbps 'pro' synchronous SSDs.

AJA System Test measures large sequential read and write speed (which emulates playback and capture of HD video). Settings used included 8GB File Size, 2048x1556 10-bit RGB Video Frame Size, file system cache Disabled. The results in the graph are AVERAGE SUSTAINED speeds, not just PEAK speeds. (HIGHEST number means FASTEST in megabytes per second.)

Intech's QuickBench - The Standard Test includes a mix of small random transfers from 4K to 1024K. Not all disk transfers are large and sequential. OS X 'housekeeping' is case in point. We post the average of 5 cycles. (HIGHEST number means the FASTEST in megabytes per second.)

LEGEND of GRAPHS

miniSwap/U3*2 = two FirmTek miniSwap/U3s with 6Gbps Samsung 840 Pro 256G SSDs in RAID 0 set -- each connected directly to a USB 3.0 port

LBD TB*2 = LaCie Little Big Disk Thunderbolt with dual 6Gbps C400 Micron 256G SSDs in RAID 0 set



Rugged TB*1 = LaCie Rugged USB 3.0 (+TB) with single 6Gbps Micron C400 256G SSD (using TB port)

Elgato TB*1 = Elgato Thunderbolt with single 3Gbps SanDisk Ultra 240G SSD

GoFlex TB*1 = Seagate GoFlex Thunderbolt adapter with 6Gbps bare OWC Electra async 240GSSD



miniSwap/U3*1 = FirmTek miniSwap/U3 with single 6Gbps Samsung 840 Pro 256G SSD

Rugged U3*1 = LaCie Rugged USB 3.0 (+TB) with single 6Gbps Micron C400 256G SSD (using USB3 port)



Results in the graphs are from the 2012 Retina MacBook Pro. We also tested on the 2012 iMac, measuring essentially the same results.

SO WHO WINS?

Turns out that the newest, latest USB 3.0 bus powered notebook storage devices are as fast or faster than their Thunderbolt counterparts. How is this possible when Thunderbolt is rated at 10Gbps (theoretical) and USB 3.0 is rated at 5Gbps (theoretical)? Two reasons: a) no single 6Gbps SSD can go faster than about 500MB/s (or 5Gbps) and b) improved USB 3.0 controllers squeeze the full potential from USB 3.0.

What about the dual drive scenario? How could the dual USB 3.0 RAID 0 keep up with the Little Big Disk Thunderbolt (10Gbps) RAID 0 unit? That's because the two miniSwap/U3s were being fed by dual 5Gbps USB 3.0 ports (or 2 x 5 = 10Gbps). Though the emphasis in this article is on "fastest BUS POWERED notebook storage," we overlooked the fact that the Little Big Disk Thunderbolt RAID unit required an AC adapter. At any rate, in this "boxing match," the miniSwap/U3s won three out of four "rounds."

WHAT IF I USE HDDs?

We did some quick benchmarking of three notebook HDDs (WD Green 2TB, WD Black 750GB, Seagate Hybrid 1TB). They clocked 113MB/s, 131MB/s, and 118MB/s respectively on the large sequential transfers. The SSDs were 5 to 10 times faster on the small random transfers. However, if capacity and price is your priority, these notebook HDDs will do the job.