G-Technology G-RAID with Thunderbolt 8TB full review

G-Technology majors on building external storage products in premium enclosures. The G-RAID is one such product, a smart aluminium unit closely modelled on the now-classic Power Mac and Mac Pro design, replete with wraparound aluminium sheet cover, and perforated ends and sides. 

Now the G-RAID is available with the world’s fastest interface for desktop computing: Thunderbolt. 

See also:  Group test: what's the best portable hard drive?

As the name betrays, the G-RAID contains more than one disk – two, in fact – that can be configured in a RAID format to increase either speed or reliability.

Best performance is available by setting up in RAID 0, where data is striped between the two disks. This provides storage capacity that is the sum of the two disks inside. We reviewed the unit branded ‘8TB’, which includes two of the very latest 4TB Hitachi 3.5in SATA disks. 

You can also find it in 4TB and 6TB versions, which include a pair of 2TB and 3TB disks respectively. Disks are sourced from Hitachi, perhaps unsurprising given that G-Technology is now a subsidary company of Hitachi GST.

Unlike some professional storage products, including G-Technology’s own earlier eSATA/FireWire 800 version of the G-RAID, the G-Raid with Thunderbolt includes no built-in hardware RAID controller. Instead, the volume configuration is set in software, using OS X’s Disk Utility.

Our sample was ready configured for RAID 0 out of the box. Setup thus, you can expect the very best performance, even as the disks become full, at the expense of any data security. If one of the two disks should fail, you’ll lose all your data.

An alternative is RAID 1, which effectively mirrors data between disks. This provides the best security against data loss, although total storage is now only equal to the capacity of one single disk.

G-Technology G-RAID with Thunderbolt: Build and features

Build quality is superb, a fitting tribute to Apple’s original industrial design. From the front, a white LED glows to indicate power. And just to remind you of its calibre, a blue-and white Intel flash symbol brands the drive for its Thunderbolt interface.

Around the back, we find a DC power socket for the external mains adaptor, an Apple-like stainless-steel On press-button switch, Kensington lock slot – and the all-important Thunderbolt interface. There are two Thunderbolt ports, an important asset to allow the G-RAID to sit in the middle of a chain of up to six Thunderbolt devices.

Missing from the drive are any legacy ports to allow use with a USB or FireWire-equipped Macs. Ownership of this drive is a indeed a commitment to the Thunderbolt connection.

Unlike the single-disk versions of G-Technology’s drives, this double-stacked unit also adds a small diameter cooling fan to keep the disks from overheating.  

In use, this ran relatively quietly and didn’t intrude much above the sound of the disks themselves. And despite their high-spec 7200rpm spindle-speed rating, even the Hitachi Deskstar 4TB drives inside were not conspicuously noisy.

G-Technology G-RAID with Thunderbolt: Performance

As a performance piece of machinery, we tested the G-Raid with Thunderbolt in its default state with RAID 0. And here, it delivered all we could hope of a two-drive hard-disk solution. More than we’d expected, in truth.

As the host Mac may have some influence on the performance of software RAID setups, we used highly specified computers for testing: a MacBook Pro 15in (Early 2011) with quad-core 2.2GHz Intel Core i7, and Mac mini (Mid-2011) with dual-core 2.7GHz Intel Core i7 processor and Intel 520 Series SSD.

Our original tests were made with the QuickBench tool for OS X, which reported uncannily fast performance. With speeds exceeding 500 MBps, it became obvious that due to the software RAID configuration, we were actually seeing the speed of the disks’ buffer cache, which could not be disabled in a simple synthetic benchmark setup.

Instead we turned to real-world data transfer tests. And here the G-RAID with Thunderbolt was still turning in remarkably good results.

A test folder comprised a rip of a Blu-ray film, measuring 23.36GB. This was transferred from the Mac mini to the G-RAID in 71 secs, suggesting an average write speed of 329 MBps.

Copying the directory back to the Mac to test the drive’s read speed took 76 sec, equivalent to around 307 MBps.

To duplicate the same file on the G-RAID, a test of simultaneous read/write, took 150 sec, making an average overall speed of 156 MBps.

A pair of disks in RAID 0 typically give around 50 percent speed boost over a single drive. With speeds exceeding 300 MBps, it’s possible we were still seeing the work of disk memory cache. However, these were real transfer tests, which suggest that these are real benefits that can be found when using this drive.

Mirror, mirror

Returning to QuickBench, we measured performance of the G-RAID with Thunderbolt when configured in RAID 1. 

This should reveal the performance of a single drive, without the accelerated benefit of striping between two disks.

Here, the lab tests suggested strong read and writes at up to 177 MBps.

In the BD transfer test, the Blu-ray folder was read in 140 secs and could be written to the drive in 142 secs, giving real-world transfers speeds of around 167 MBps.

This review was updated Friday 27 April with the addition of real-world performance tests, to replace erroneous figures recorded in synthetic benchmark testing.


G-Technology G-RAID with Thunderbolt 8TB: Specs

  • 8TB external storage
  • 2 x 4TB Hitachi Deskstar 7K4000
  • 2 x Thunderbolt ports
  • software RAID to be configured in Mac OS X
  • external 12V DC power adaptor
  • 235 x 130 x 85mm
  • 2437g