SanDisk Professional PRO-G40 ThunderBolt 3 Dual Mode Portable SSD Review – Unbelievable 3.1GB/s Data Transfer Speeds

Hot on the heals of one of the best examples of pure storage gear that we have ever had in our hands (SanDisk Professional PRO-BLADE), Western Digital sends us along their newest SanDisk Professional PRO-G40 Portable SSD for a quick look.  Let’s start this report off by saying that SanDisk Professional gear is not for the faint of heart.  It is intended for content creators and media professionals and is just a bit more expensive,  but that can only be expected with this gears no-holds barred quality build, performance and innovation.

The SanDisk Professional PRO-G40 is yet another fine example of the brand name with its solid aluminum casing that plays its part in gaining the devices IP68 rating (4000lb crush/3m drop/1m water/dustproof).  For its base, there is a soft liquid silicone rubber which has a great feel along with a metal reinforced Type-C port on the bottom end of the unit.


This portable SSD is available in 1/2TB capacities and comes with a 20cm/8″ ThunderBolt 3 cable which is probably the only negative we could find in the PRO-G40.  We would like to have seen a much longer cable for this bus-powered SSD.


We were unable to disassemble the PRO-G40, regardless of how those four Torx screws tempted us on the surface.   We think this is a clamshell design, with the liquid silicone rubber casing glued to the unit making it impossible to open.  We are aware, however, that this SSD uses a SanDisk SN750e M.2 SSD (reviewed here) , along with an Intel JHL7440 ThunderBolt 3 ‘Titan Ridge’ controller chip and ASMedia ASM2362 USB 3.2 controller chip to provide ‘dual-mode’ performance.


The SanDisk Professional PRO-G40 Portable SSD is marketed as a dual-mode device which means that it will provide the industries fastest data transfer speeds while being used as a ThunderBolt 3 device (40Gbps) up to 2.7GB/s (wait for it), or in USB 3.2 mode (10Gbps) where it performs up to 1GB/s.  This is the mark of SanDisk Professional.

The PRO-G40 is available at Amazon for $229 (1TB) and $449(2TB) which, as we have already mentioned is a bit steep, but that’s what one might expect when they look for the best.


Crystal Disk Info is a great tool for displaying the characteristics and health of storage devices. It displays everything from temperatures, the number of hours the device has been powered, and even to the extent of informing you of the firmware of the device.


We can see that the SanDisk Professional PRO-G40 Portable SSD is PCIe 3 x 4 which is the only way top ThunderBolt performance could be achieved. As well, this device uses the NVMe 1.3 protocol and is TRIM capable.

We might mention, however, that to achieve top performance with this SSD, one has to go into their system Control Panel/Device Manager/Disk Drives/SanDisk PRO-G40/Policies and click on ‘Better Performance’ and check the ‘Enable Write Caching on  this Device’ box, as shown here:


Let’s take a look at some performance specs:

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