The SanDisk Extreme Pro USB4 SSD is a visually appealing, durable, and relatively affordable external SSD boasting 40Gbps speeds. However, our testing revealed connection inconsistencies, sometimes dropping to 10Gbps or even 5Gbps. Even at its peak 40Gbps performance, it lagged behind competitors.
SanDisk Extreme Pro USB4 SSD Features
The SanDisk Extreme Pro USB4 SSD shares the same shape, style, and dark gray with copper accents as its predecessors, but it’s noticeably larger. Measuring 5.4 inches long, 2.2 inches wide, and 0.45 inches thick, it weighs approximately 5.4 ounces. This robust build conveys a sense of quality. The textured silicone covering provides a comfortable and secure grip.
alt The SanDisk Extreme Pro USB4 SSD features a distinctive design and textured silicone for enhanced grip.
This drive utilizes the high-end 40Gbps version of the USB4 protocol. While 20Gbps USB4 implementations exist, they are less common. Future USB4 v2 and Thunderbolt 5 promise 80Gbps speeds, but compatible SSDs are still rare.
SanDisk offers a five-year warranty for the Extreme Pro USB4 SSD, likely subject to TBW (Terabytes Written) limitations, although this isn’t explicitly stated. Based on the write speed dropping to 550MBps after the secondary cache, we suspect it uses TLC NAND flash, which typically has a 600TBW endurance rating per terabyte.
SanDisk Extreme Pro USB4 SSD Pricing
The SanDisk Extreme Pro USB4 SSD is priced at $280 for the 2TB model and $430 for the 4TB model. This is comparable to pre-built competitors like the Adata SE920 and OWC Envoy Pro FX but not as budget-friendly as the Corsair EX400U. DIY options like the Ugreen CM642 offer lower costs but require manual SSD installation. Overall, the Extreme Pro SSD’s pricing is competitive within the USB4 market.
SanDisk Extreme Pro USB4 SSD Performance
While fast, the Extreme Pro USB4 SSD didn’t match the performance of other high-speed USB4 drives in our tests. It also trailed some 20Gbps SSDs in real-world file transfers. More concerning were the connection stability issues.
Using the included 40Gbps cable, the drive connected at only 10Gbps on one Thunderbolt 4 port on our test system and 5Gbps on another, triggering a Windows warning about potential performance limitations. However, it achieved full 40Gbps speeds on an M1 Max Mac Studio’s Thunderbolt 4 port with the same cable.
Switching to a high-quality Thunderbolt 4 cable resolved the issue on the PC test bed, enabling consistent 40Gbps connectivity. However, a subsequent test with the same Thunderbolt 4 cable resulted in reduced speeds again. This suggests potential compatibility issues with certain Thunderbolt 4 implementations.
alt CrystalDiskMark sequential tests show the SanDisk Extreme Pro USB4 SSD performing reasonably well, but not leading the pack.
In CrystalDiskMark’s sequential tests, the drive performed adequately at 40Gbps but wasn’t the fastest. Its main weakness was single-queue/single-thread writing, a performance metric relevant to typical Windows operations.
alt Random 4K tests highlight a significant weakness in single-thread write speeds.
Random 4K tests showed a similar pattern, with the single-thread write speed lagging considerably behind the competition. This low score, consistently reproduced in multiple tests, likely contributes to the slower real-world write performance under Windows.
alt Real-world file transfer tests further demonstrate the impact of the slower write speeds.
In our 450GB write test, the Extreme Pro USB4 SSD completed the transfer in a respectable but not impressive time, falling behind some 20Gbps SSDs.
alt The 450GB write test reveals a middling performance compared to other drives.
Should You Buy the SanDisk Extreme Pro USB4 SSD?
The SanDisk Extreme Pro USB4 SSD offers a compelling combination of style, durability, and reasonable pricing for a USB4 drive. It’s generally faster than most 20Gbps USB 3.2 Gen 2×2 SSDs.
However, the connection inconsistencies are a concern, and faster 40Gbps alternatives are available. We recommend waiting for a revised version or considering other options for optimal performance and reliability.
