When we return to conventional spinning disks, the difference between the performance of these are capable, and NAND flash is enormous.

That makes the PRO-G40 the fastest external Thunderbolt drive we’ve tested recently by some margin. The only drive we’ve seen that is close to this is the OWC Envoy Pro FX, and that costs even more than the PRO-G40.But this product has issues with some of the workflow thinking here that SanDisk entirely owns. These include no easy means to identify one Mag from another, that a Transport carrier was designed without any included means to mount it on a camera, and that without a Pro-Blade Transport or Pro-Blade Station, it is impossible to access a Mag. That said, the OWC Envoy FX external SSD isn’t that far behind these numbers, and the limiting factor to speed is Thunderbolt bandwidth, not the drives.

SanDisk delivers the drive pre-formatted with APFS for the Apple macOS, something that will cause some confusion with Windows owners who aren’t familiar with how to reformat drives. The Transport features an aluminium heat sink to maintain the Mag’s temperature and therefore continued operation. Consequently, the Mag only gets mildly warm during use.Another issue is that when you look through the NVMe drives from Western Digital manufacturers, the biggest capacity is 4TB, and that’s the largest SSD Mag on offer. Corsair and Sabrent have offered 8TB NVMe modules for some time, and larger capacities are around the corner, so SanDisk needs to tell its in-house supplier to wake up. And for those wondering if this high pricing is Brexit related, it isn’t. The prices for this range in France are equally inflated, being €163.99,€264.99, €410.99 and €769.99. And, competing against its own products, Western Digital makes the excellent My Book Duo, where the 16TB drive (2 x 8TB) is a little more than the 18TB G-DRIVE Desktop Drive but offers a resilient mirroring option and allows the users to change the drives. As a USB drive, these numbers are solid and equivalent to those that we’ve seen from the Crucial X8 and its like. There are faster USB drives that use the USB 3.2 Gen 2x2 standard, such as the PNY EliteX-PRO and Kingston XS2000. For those curious, Thunderbolt-connected SSDs can be three times these speeds, something to consider for those that have that port and can afford those drives.

We’ve noticed that the price of this drive has been reduced recently, reflecting the reduced cost of NAND modules and high levels of competition in this sector. The shaping of the Mags means that there is only one orientation that they go, and once inserted into Pro=Blade Station, a small LED above the slot indicates that they’ve been recognised, and this flashes when they’re in use. So much of the success or not of this hardware is down to the Pro-Blade SSD Mags, and what they offer that simple external SSD storage doesn’t.

But the same as that counterpart, SanDisk doesn’t provide a pouch or case to carry the drive and its cables, a niche that some third party will undoubtedly fill.