Review: G-Tech G-Dock ev with Thunderbolt

Standalone drive testing

We ran a series of tests on a single G-Drive unit, to see how it performed via USB 3 with the included SuperSpeed cables. The cables are short, about a foot in length, and allow a small loop so that both G-Drive modules fit nicely side by side on top of our Mac Mini desktop’s brushed aluminum case.

Using the Blackmagic Disk Speed Test (version 2.1.1) on OS X Mavericks (10.9.1), we ran both a single-drive test and a software-based RAID 0 test.

A single G-Drive EV was able to generate approximately 35 frames per second (fps) of 720p50 at 10-Bit YUV 4:2:2 on the speed test, but fell below full frame rate for 12-Bit RGB 4:4:4. It also wasn’t able to match the needed frame rate for 720p59.94 (US-based 29.97 fps) or any 1080P frame rates beyond 22 fps.

Overall reads and writes were almost equal at around 120 megabytes per second (MB/sec).

For our next baseline test, we wanted to see what types of speed we could generate from two G-Drives, both connected via the USB 3 cables to the Mac Mini or MacBook Air and then combined into a RAID 0 via Apple’s internal RAID software found in Disk Utility.

We striped the drives in Disk Utility and then performed the same speed tests. This combination of two drives acting as one (RAID 0) gave the G-Drives significantly better results. In 10 Bit YUV 4:2:2, the drives were able to accomplish 2K up to 25 fps, clearing every hurdle except for 1080p50 and 1080p59.94 content.

RAID 0 reads and writes were a bit more than double, which is in line with software-based RAID striping, at just over and under 250MB/sec, respectively.
In-chassis drive testing. We then slid the two G-Drive units into the G-Dock, after removing the dust cover on each (noted above), and reformatted the drives into a RAID 0 again. We needn’t have done this, as the G-Dock identified both slices of the striped virtual drive, but we wanted to test a fresh RAID 0 configuration to see whether the G-Dock added anything to the speed mix.

The Blackmagic Disk Speed Test results for the G-Dock RAID 0 were exactly in line with our standalone software RAID 0 tests: reads came in at 255 MB/sec while writes were 250 MB/sec. The drives could handle the same frame rates in the G-Dock, but appear to gain no additional speed being in our out of the dock.

Bottom Line

Based on our performance tests, and the fact that the USB 3 SuperSpeed connector provides both data and power connectivity, we would tend to use the two G-Drive modules in standalone mode, or striped as RAID 0 configurations. We found that copying large files to the drives is faster in the G-Dock, but only by about ten percent over the standalone configuration.

As such, we could see using two G-Drive modules in a software-based RAID 0 configuration in the field, without the G-Dock, and then using the G-Dock itself as a convenient mounting system for a combined, single daisychain approach to connect a monitor and the drives via Thunderbolt.

Having said that, is the G-Dock worth the extra money for just two 1 terabyte drives? Some outlets are sweetening the pot by selling the unit with 4 x 1TB G-Drives, but the compelling argument to us would be a significantly faster throughput in the G-Dock versus in a standalone mode. We just don’t see that level of benefit is worth spending an extra $400-500 over the street price of other portable 1TB drives.