Review: Sonnet Fusion PCIe 1TB and G-Drive Mobile Pro 500GB

By Brady Betzel

There are a lot of external Thunderbolt 3 SSD drives out in the wild these days, and they aren’t cheap. However, with a high price comes blazingly fast speeds. I was asked to review two very similar Thunderbolt 3 external SSD drives, so why not pit them against each other? Surprisingly (at least surprising to me), there are a couple of questions that you will want the answers to: Is there thermal throttling that will lower the read/write speeds when transferring large files for a sustained amount of time? Does it run so hot that it may burn you when touched?

I’ll answer these questions and a few others over the next few paragraphs, but in the end would I recommend buying a Thunderbolt 3 SSD? Yes, they are very, very fast. Especially when working with higher resolution multimedia files in apps like Premiere, Resolve, Pro Tools and many other data-intensive applications.

Sonnet Fusion Thunderbolt 3 PCIe Flash Drive
Up first (only because I received it first) is the Sonnet Fusion external SSD. I was sent the drive in a non-retail box, so I can’t attest to how it will arrive when you buy it in a retail setting, but the drive itself feels great. Like many other Sonnet products, the Fusion drive is hefty — and not in an overweight way. It feels like you are getting your money’s worth. Unlike the rubberized exterior of the popular LaCie Rugged drives, the Sonnet Fusion is essentially an aluminum heat sink wrapped around a powerful 1TB, Gen 3 M.2 PCIe, Toshiba RVD400-M22280 solid state drive. It’s sturdy and feels like you could drop it without receiving more damage than a little dent.

Attached to the drive is Sonnet’s “captive” Thunderbolt 3 cable, which I assume means the cable is attached to the external drive casing but can be removed without disassembling the case. I think more cable integrations should be called captive, it’s a great description. Anyway… the Thunderbolt 3 cable can be replaced/removed by removing the small four screws underneath the Fusion. It’s attached to a female Thunderbolt 3 port inside of the casing. I really wish Sonnet had integrated the wrapping of the cable around the drive, much like the LaCie Rugged drives in addition to the “captive” attachment. This would really help with transporting the drive and not worrying about the cable. It’s only a small annoyance, but since I’ve been spoiled by nice cable attachment I kind of expect it, especially with drives with a price tag like this. The Sonnet Fusion retails for $899 through stores like B&H, although I found it on for $799. Not cheap for an external drive, but in my opinion it is worth it.

The Sonnet Fusion is fast, like really fast, as in the fastest external drive I have tested. Sonnet claims a read speed of up to 2600MB/s and a write speed of up to 1600MB/s. The only caveat is that you must make sure your computer’s Thunderbolt 3 port is running x4 PCIe Gen 3 (four PCIe lanes) as opposed to x2 PCIe Gen 3 (only two PCIe lanes). If this is the case, your speed will be limited to around 1400MB/s as opposed to the proposed 1600MB/s write speed. You can find out more tech specs on Sonnet’s site. In addition you can find out if your computer has the PCIe lanes to run the Fusion at full speed here.

When testing the Sonnet Fusion I was lucky enough to have a few systems at my disposal: a 2018 iMac Pro, a 2018 Intel i9 MacBook Pro and an Intel i9 Puget Systems Genesis I with Thunderbolt 3 ports. All the systems provided similar results, which was nice to see. Using the AJA System Test, I adjusted the settings to 3840×2160, 4GB and ProRes 4444. I used one reading for an example image for this review, but they were generally the same every time I ran the test. I was getting around 1372MB/s write speed and 2200MB/s read speed. When transferring files on the Finder level I was consistently getting about 1GB/s write speeds, but it’s possible I was being limited by the write speed from the internal SSD! Incredible. For real-world numbers, I was able to transfer about 750GBs in under five minutes. Again, incredible speeds.

The key to the Sonnet Fusion SSD and what makes it a step above the competition is its enclosure acting as a heat sink in its 2.8×4.1×1.25-inch form factor. While this means there are no fans to increase the volume, it does mean that the drive can get extremely hot to touch, which can be an issue if you need to pack it up and go, or if you put it in your pocket (be careful!). This also means that with great heat dissipation comes less thermal throttling, which can slow down transfer speeds when using the drive over longer periods of time. This can be a real problem in some drives. Also keep in mind that this drive is bus powered and Sonnet’s instruction manual specifically states that it will not work with a Thunderbolt 2 adapter. The Sonnet Fusion comes with a one-year warranty that you can read about at this link.

G-Drive Mobile Pro SSD 500GB
Like the Sonnet Fusion, the G-Drive Mobile Pro SSD is a Thunderbolt 3 connected external hard drive that touts very high sustained transfer speeds of up to 2800MB/s (read speed). The G-Drive is physically lighter than the Sonnet, and is cheaper coming in at about 79 cents per GB or 68 cents if you purchase the 1TB version of the G-Drive — as compared to the Sonnet Fusion’s 88 cents per GB. So is this a “get what you pay for” scenario? I think so. The 500GB version costs $399.95 while the 1TB version retails for $699.95. A full $100 cheaper than the Sonnet Fusion.

The G-Drive Mobile Pro has a slender profile that matches what you think an external hard drive would look like. It measures 4.41x 3.15x.67 inches and weighs just .45 lbs. The exterior is attractive — the drive is surrounded by a blackish/dark grey rubberized plastic with silver plastic end caps. There are slits in the top and bottom of the case to dissipate heat, or maybe just to show off the internal electric blue aluminum heatsink. The Thunderbolt 3 connection is on the rear of the housing for easy connection with a status LED on the front. The cord is not attached to the drive, so there is a large chance of being misplaced. Again, I really wish manufacturers would think about cable storage and placement on these drives — LaCie Rugged drives have this nailed, and I hope others follow suite.

Included with the G-Drive Mobile Pro is .5 meter Thunderbolt 3 cable. It comes with a five-year limited warranty described on the included pamphlet that just may feature the tiniest font possible. The warranty ensures that the product is free from defects in materials and workmanship, with some exclusions including non-commercial use. In addition, the retail box shows off a couple of key specifics including “durable, shock resistant SSD” while the G-Technology website boasts of three-meter drop protection (on a carpeted concrete floor), as well as 1,000-pound crush-proof rating. Not sure if this is covered by the warranty or not, but since there really aren’t moving parts in an SSD, I don’t see why this wouldn’t hold up. An additional proclamation is that you can edit multi-stream 8K footage at full frame rate. This may technically be true in a read-only state but you would need a super-computer with multiple high-end GPUs to actually work with this size media. So take that with a grain of salt — not just on this drive but with any.

So on to the actual nuts and bolts of the G-Drive Mobile Pro SSD. The drive looks good on the outside and is immediately recognized by any Mac OS with direct Thunderbolt 3 connection (like all bus-powered drives). If you are using Windows you will have to format the drive before you can use it. G-Technology has an app to make that easy.

When doing real-world file transfers I was getting around the 1GB/s transfer speed consistently. So, theG-Drive Mobile Pro SSD is blazing fast. I was transferring 200GB of files in under two minutes.

Summing Up
In the end, if you haven’t seen the speed difference coming from a USB 3.0 or Thunderbolt 2 drive, you must try Thunderbolt 3. If you have Thunderbolt 3 ports and are using old Thunderbolt 2 drives, now is the time to upgrade. Not only can you use either of these drives like an internal drive, but if you are a Resolve colorist or a Premiere editor you can use these as your render cache or render drive. Not only will this speed up your coloring and editing, but you may even start to notice less errors and crashes since the pipes are open.

Personally, I love the Sonnet Fusion drive and the G-Drive Mobile Pro. If price is your main focus then obviously the G-Drive Mobile Pro is where you need to look. However, if a high-end look with some heft is your main interest, I think the Sonnet Fusion is an art piece you can have on your desktop.

Brady Betzel is an Emmy-nominated online editor at Margarita Mix in Hollywood, working on Life Below Zero and Cutthroat Kitchen. You can email Brady at Follow him on Twitter @allbetzroff.

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