SanDisk 4TB SSD PCIe 4.0 NVMe M.2 2280

The SanDisk Optimus GX PRO 850X is a 4TB PCIe 4.0 drive with excellent speed and a best-in-class feature set. It scores 82.7 overall, with random performance near the top of the charts. The price is steep and portability is weak, so it's best for desktop creators who need capacity and encryption.

Sequential speeds are right where you'd expect for a high-end Gen 4 drive: 7,300 MB/s read and 6,600 MB/s write. Random IOPS land at 1,200K read and 1,100K write, which puts it in the 96th percentile for random performance, one of the best on the market. The TLC NAND and DRAM cache keep things snappy under load, and DirectStorage support means it's ready for games that lean on fast storage. Endurance is more middle of the pack at 400 TBW for the 4TB model, which is fine for most people but not a headline number.

Against the Samsung 9100 PRO, the SanDisk holds its own on features and random performance but gives up some endurance and brand recognition. The Kingston FURY Renegade G5 and WD_BLACK SN850X are both strong Gen 4 alternatives that often cost less, though the SanDisk's feature percentile beats them. The Crucial T700 pushes into Gen 5 territory with higher peak speeds, but you'll pay for that too. The Seagate FireCuda 530R is a solid budget-conscious pick with similar capacity. For pure speed per dollar, the SanDisk isn't the winner. For a loaded 4TB drive with encryption and a heatsink, it's a compelling package.

This is where things get tricky. The USD price swings from $850 to $1,578 depending on the vendor, and the best deal in our data is at Newegg. That spread is wild for the same drive. Affordability sits in the 6th percentile, meaning almost everything else in this category costs less. You're paying a premium for the capacity and the feature set, not for raw value. If you need 4TB of fast Gen 4 storage and want the extras, it's justifiable. If you're just gaming, cheaper options will feel nearly identical.

The SanDisk Optimus GX PRO 850X is a 4TB PCIe 4.0 drive aimed squarely at gamers and creators who want big capacity without giving up speed. It hits 7,300 MB/s reads and 6,600 MB/s writes, which puts it near the top of the Gen 4 charts. The feature set is loaded too, with a heatsink, hardware encryption, and DRAM cache all in the box.

Our database scores it 82.7 out of 100 overall, with workstation use at 84.2 and gaming at 82.8. The feature ranking is basically best-in-class at the 99th percentile, and random performance is a standout too. But the price is rough, and portability is not this drive's thing.

Skip this if you need a portable drive or plan to use it in a thin laptop, the portability score of 20.8 is one of the worst we've seen for this category. Also skip it if you're on a budget, since nearly every competitor costs less. If you don't need hardware encryption or a bundled heatsink, you're paying extra for features you won't use.

Buy this if you want a big, fast, feature-rich Gen 4 drive and don't mind paying for it. Creators who need hardware encryption and lots of space will get the most out of it. Gamers who just want fast load times can save money elsewhere and barely notice the difference.