Review: G Dock ev with Thunderbolt

For several months, Apple has been promising the new Mac Pro will be “coming in December.” I just visited the Apple web site, and they are now promising delivery in February.

I keep thinking that this new machine might be the perfect New Year’s present for my home office because it’s slick, and it’s cylindrical and black, and mysterious looking. It’s also amazingly fast, and speed is an issue for many of my photographic and video projects.

When I look at the specs of the new Mac Pro, I find myself dizzy with information. There’s a newer, faster USB bus, and a newer, faster video bus, and a newer, faster Thunderbolt bus on this machine with speeds that promise many Gigabits per second of file transfer speed. I have not yet priced my configuration of the new Mac Pro, but I suspect that it might involve a second mortgage to get all the RAM, video processors, etc., (and I confess that I don’t even understand some of the features of the new machine).

The one thing that is obvious from the new shape and size of the machine is that there is no place to put a hard drive. The machine itself runs with the equivalent of a hard drive in what is called PCIe-based flash storage that is configurable up to 1TB. This is a flash RAM “hard drive” that Apple says is over four times faster than current SSD memory.

With no place to put even one conventional hard drive, all of us Mac Pro junkies (and those of us who use Thunderbolt on our MacBooks and iMacs) will need a new location for data storage. On my current Mac Pro I have four internal 4TB drives, one external 8TB TIme Machine drive, one external 2TB drive, and a NAS (Network-Attached Storage) server under my desk with an additional 14 TB of storage. That translates into almost 40TB of storage directly connected to my machine. And, when (if) I get my new Mac Pro, I will need to move all of that to some form of storage that the new computer can accept.

There is no FireWire on the new Mac Pro, alas, which means that I will have to come up with a method for connecting my Nikon CoolScan, my Epson 2400 ink-jet printer, and my MOTU audio interface device to the machine (there is an adapter available now that connects FireWire 800 over Thunderbolt; I will assume that this will work on the Mac Pro).

So, thinking about storage, I need a new strategy for external and working high-speed storage. The NAS is great for long-term storage, but it’s limited by the speed of Ethernet (the new MacPro has Gigabit Ethernet). I need something that can move data to the new computer at speeds that make video editing practical. I need a device that can feed my high-resolution digital photos (25-60 MB each) by the thousand to the computer for my GigaPan processing—making panoramic photos that are often 20-40 GB in size. For those tasks I will need to use Thunderbolt (the new machine has Thunderbolt 2, which is faster).

Thunderbolt hard drives were slow to arrive on the scene. I have had my MacBook Air with Thunderbolt for two years now, and I looked occasionally for a Thunderbolt drive to use with that machine, but came up empty handed several times. I finally found a drive/dock combination from G-Technology that is both practical and effective. That device is the answer to my portable computing needs and will eventually deliver the blazing transfer speeds of my new Mac Pro.

What I found tantalizing about the G Dock ev storage device is that it provides flexibility for field work—USB-3—for the small drive inserts, and Thunderbolt connectivity for base station work. The same drive inserts work in both situations, but the configuration is different depending on your work style.

In the professional motion picture industry, there used to be a person whose job title was “loader,” the person who loaded rolls of film into camera magazines, then unloaded the exposed film into cans and bags for transport to the processing lab. The modern equivalent of that job is called “DIT” (Digital Intake Technician), the person who unloads the contents of memory devices onto a waiting computer hard drive, and then logs the digital data, clears the memory devices and hands them back to the camera operator for more data. These DITs need a technology like this new device from G-Technology. Inexpensive 1TB drives can be connected with USB-3 to a portable computer, and used to capture data from video storage. Those drives could then be stacked like cordwood, labeled for further processing back in the editing suite.

In the editing suite, the drives would be inserted into the G-Dock connected by Thunderbolt to a Mac Pro. The speed of transfer is theoretically faster, but is practically limited by the speed of the internal hard G-Drive ev units, which is 7,200 rpm, as fast as hard drives go. G-Technology rates this dock at a maximum speed of 10Gb/sec. which is half the possible speed of Thunderbolt technology.

I tested the speed of the G Dock in a panoramic photo workflow. This, I believe, is a good example because the photo has lots of separate files and folders, and copying these would require a great deal more computer overhead to manage the separate documents. And, though I have access to various computers, including iMacs with Thunderbolt connectors, I chose the MacBook Air because its internal SSD drive is faster than the iMacs’ drives (theirs are 5,400 rpm mechanical hard drives, which are slower).

Recently, I took a GigaPan image of a local historic site. My photo is comprised of 560 images, each one about 25 MB on disk. I copied all of these images to my MacBook Air, then processed the GigaPan with that company’s software GigaPan Stitch eFX. The resulting photo is 30.8 GB after cropping. As GigaPan Stitch software runs, it creates a mountain of reference files, each representing a portion of the final image, and it stores them all. In this example, that software created a total of 118,112 separate files for a total of 107.63 GB (the 30.8 GB final photo included).

After completing the GigaPan panorama, I ran my test of the G-Dock, which was connected to the MacBook Air with Thunderbolt (the only Thunderbolt device connected). My first test with the G-Dock was as two separate 1TB drives. The 107.63 GB of data transferred to one of the drives in the dock in 14 minutes, 4 seconds. This compared favorably to the time it took in a separate test to write to a portable hard drive, which was 51 minutes for the same transfer over USB-2, and 18 minutes over FireWire 800.

G-Technology lists the maximum transfer speed of the G-Dock at 10 Gb/sec, which translates to approximately 1.25GB per second at 8 bits per byte (this speed ignores any protocol data).

Theoretically, the drive should have transferred the 107.63 GB in 86 seconds, or about 1.5 minutes. So, what causes the drive to take 14 minutes to transfer the actual material compared to the theoretical speed of 1.5 minutes? I asked a networking expert friend about this, and he said that there are various factors conspiring to slow the transfer, including the 118,000 files, the infrastructure and communication protocols, checksums, error-correction and prevention, and limitations of the physics of drive speed. He also mentioned that the SATA controllers in the dock might be slowing the data to the drives slightly. Overall, he thought that 14 minutes for a task like mine seemed pretty impressive.

Once that test was complete, I erased the two drives in the D-Dock, and set them up as a striped RAID pair, using the Macintosh Disk Utility software. With a striped RAID, the data can be written to both drives simultaneously, which should make the transfer process go significantly faster.

Once designated as a RAID, I made the same transfer of 107.63 GB to the G-Dock in seven minut
es, half the time of the previous test. The process lost nothing to the various protocols in this test.

The use of this dock as a RAID array is a smart move for those who need brute speed, like the DITs mentioned above. The only potential problem is risk. With a striped RAID pair, there is no back-up and no redundancy. If one drive fails or is corrupted, all of the data on both physical drives goes with it.

BUT… I was going for raw speed, and the RAID configuration gave me what I was seeking. With this technology I can accomplish several things: I can transfer data from my MacBook Air to an individual drive over USB-2, I can attach one or two of the G-Drive ev inserts to the G-Dock, and then transfer that data back to my desktop computer over Thunderbolt at tremendous speed, and when the drives are full, I can add new ones. Practically speaking, the 1TB G-DRIVE ev USB 3.0 hard drive inserts are cheap enough – $199.95 – to dedicate to a single video project. They are small, light, and solidly-made. By purchasing a pair of them I can make RAID drive sets and double my speed.

If—and that’s a pretty big if—I get the new Mac Pro in February, I will need something like the G-Dock with Thunderbolt, and I will appreciate the impressive speed of the Thunderbolt technology combined with its 7200-rpm drives.


The G-Dock comes with all necessary cables: one short Thunderbolt cable, two USB-3 to standard USB cables, Power cord, Power Supply with cord to the dock unit.


This is the back of the G-Dock. It has receptacles for two Thunderbolt cables, which can be daisy-chained to other devices.


The two separate 1TB G-DRIVE ev USB 3.0 hard drive units can be inserted into the dock. Each unit can also operate as a stand-alone USB-3 drive, connected directly to a computer.


When powered-up, each drive shows a blue LED.


With a downloadable monitoring application in place, ejecting the drive on the computer causes the green LEDs to glow on the eject buttons on the right. This indicates that it’s safe to eject each disk unit.


The Thunderbolt cable is tiny, but it allows for the daisy-chain connection of multiple devices including displays and hard drives. The new Mac Pro features six of the Thunderbolt receptacles.


Each of these units is a 1TB hard drive which runs at 7200 rpm. Each can be used as a stand-alone drive with USB-3, or inserted into the G Dock to be a part of the Thunderbolt connection to a computer. They can also be paired as a RAID array to run together for additional speed.

Photos by Brian P. Lawler


Posted on: December 30, 2013

Brian P. Lawler

Brian P. Lawler is a graphic arts and prepress consultant and writer based in San Luis Obispo, California.

2 Comments on Review: G Dock ev with Thunderbolt

  1. Ugh. I had to wade down to the ninth paragraph before you stopped preattling on about your dream Mac Pro. We all get it: new Macs ship with Thunderbolt. We don’t need to know anything more than that.

    If you’re going to review something, don’t waste all that space going on about something else. 

  2. Thanks for the detail on the Mac Pro because I picked two words out of it that electrified my interest/curiosity. In detailing devices you were going to have to figure out how to hook-up/run, you mentioned Nikon Coolscan. I have one. Nikon doesn’t support Mac OSX software as far as I know. How are you A: connecting it to your current Mac Pro; B: what are you using for software;?

    A steer in the right direction would bring this scanner out of the mothballs and onto my desktop.

    Thanks –

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