Pic of the SanDisk PRO-G40 SSD on a white back ground
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SanDisk Professional PRO-G40 SSD review

Super-fast and durable SSDs are commonplace now but the super-rugged dual Thunderbolt/USB-C SanDisk PRO-G40 SSD is pretty unique and several notches above the run-of-mill offerings, as Kevin Carter discovers.

What is it?

Offering compatibility with both Thunderbolt 3 (40 Gbps) and USB-C 3.2 Gen 2 (10 Gbps), this slick-looking bus-powered NVMe SSD is a highly portable and robust drive for sharing across several devices.

Starting at £295 (inc VAT) for the 1TB rising to £441 for 2TB and a whopping £530 for 4TB, you might think this pricey but that’s because most SSD drives you’ll see advertised are USB-C only. That’s fine if that’s all you want but, what you’re paying for here is the much faster Thunderbolt 3 compatibility.

As a TB 3-enabled drive this tiny device is theoretically capable of moving 50GB of data in 30 seconds or less, so SanDisk says. That depends on your setup, of course. Speeds quoted are up to 3000 MB/s read and 2500 MB/s write, or 1050 MB/s read or 1000 MB/s write for USB-C 3.2 Gen 2 (10 Gbps). That makes it around 3/4x the speed of USB 3.x for around 2.5x the price but there are other benefits besides that blazing speed.

Astute readers will likely know that TB 4 is replacing TB 3 so this drive is likely to be on clearance soon. Both TB 4 and TB 3 have the same max 40 Gbps transfer rate and use the USB-C type connector, but TB 4 has double the minimum data transfer speeds of 32 Gbps. However, in most real-world scenarios, well for stills anyway, you’re unlikely to see much difference.

How durable is it?

Naturally, with no moving parts, it’s shockproof. It’s also dust/waterproof to IP68, the toughest and most durable protection rating for outdoor use, not the lesser IP65 rating like most other premium ‘robust’ drives. The coveted IP68 rating menials means the casing will shrug off rain, sleet and snow, like the more common IP65’s useful but less demanding protection offers, but it can also resist total immersion in water to at least 1m. That makes for some pretty bomb-proof protection.

The PRO-G40 enclosure is also said to be crushproof to 4000 lbs (1800 Kg). While it’s small enough to tuck into a back pocket I wouldn’t want to sit on it inadvertently (but nice to know it would probably survive).

What would a photographer use it for?

In theory, it’s just as at home as short-term storage or a temporary backup drive on location as it is when directly connected to compatible cameras such as the Fuji GFX 100 II for additional storage. I didn’t have a camera to hand that allows direct saving to external drives, which is a rather neat feature that’s coming to newer models.

However, I did test the PRO-G40 on a 2.9 GHz 6-Core Intel Core i9 15-inch MBP with 32GB (actually maxed out for the time) and moved a 64GB Capture One Pro Session (consisting of RAW files and few JPEGs) to it in less than 44 seconds.

SanDisk Pro PRO G40 SSD tested using the Blackmagic app.

I also ran a few tests in the essential Blackmagic Disk Test and AJA apps with super-impressive results, see screen grabs. Read and write speeds are very close to the MPB’s results. The results focus on video use but it’s nice to know that it would be fine for hybrid use.

Compare the PRO G-40 above with this result from the MPB; there’s not difference.

What’s it like to use?

In use the PRO-G40 is silent and while it does have a heat sink it never got really hot, only warm. I didn’t use it for video so it’s likely to get hotter with prolonged use, though that’s to be expected.

The enclosure is covered in a silicone-like finish which tends to pick up a little dust but is easily wiped clean and provides a non-slip grip. If you drop it the casing is rated to a 3m fall, albeit onto a carpeted concrete floor.

If there are any negatives, the device isn’t supplied with a case and the USB-C/TB3 port is exposed, but that must adhere to the IP68 rating. On the plus side, the port is rock solid with the supplied cable attached – there was no slack, no movement whatsoever.

Talking of that, one thing you might be tempted to change straightaway is the supplied (TB3) cable. While somewhat short at 9 inches (23 cm) after using it for a while I wasn’t all that worried. I have longer TB3 cables but during testing never felt I needed them.

Unsurprisingly, the supplied cable length is perfect when paired with the MBP on a desk but it is also just long enough for it to sit on the palm rest of said computer on my lap. Provided the MBP wasn’t moved too violently the grippy silicone finish of the device meant it never slipped off.


As a reviewer for over two decades, it takes quite a lot to impress me but the SanDisk PRO-G40 did just that. While pricey at first glance compared to those other tough but much slower SSDs like the Samsung T7, it’s no more expensive than similar TB3-enabled NVMe SSDs from rivals.

I’ve admired the OWC Envoy Pro SX from afar but even that doesn’t have that coveted IP68 rating. While I’m not likely to immerse the thing in water, it’s the peace of mind that counts. There’s also an industry-beating 5-year warranty instead of the more usual 3-year warranty on premium drives.

As TB4 is being phased in there are some competitive prices on the G40 if you shop around. Currently, the 2TB version seems like the best value but that may change. 


Blazing read/write speed (TB3 compared to USB-3)
Super rugged IP68 beats lesser IP ratings of rivals
Comparable in price with other TB3-enabled NVMe SSDs
Tiny – shirt pocket size
5-year warranty instead of more usual 3-year
Look for close-out deals as TB 4 replaces TB 3

Bit pricey for long-term storage but then it’s not designed for that  


Check prices and availability of the SanDisk PRO-G40 [affiliate links]  

WEX Photo (UK)| Sandisk/WD Store (UK)| Amazon (UK) (Lowest price)
B&H Photo (US) | Adorama (US)| Sandisk/WD Store (US) Currently with big savings!
Amazon (US)

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Additional test results using the AJA app for comparison.

Test results for SanDisk Pro G40 using 8K res and Canon RAW (video).


Test results for the SanDisk Pro G40 with 8K res and 16Bit RGBA selected – apparently faster than the rival TB3 enabled OWC Elite Pro SSD.