SanDisk 1TB SSD NVMe

The SanDisk Optimus GX PRO 850X is a DRAM-less drive that performs like it has DRAM, with endurance that embarrasses most competitors. At USD 218 it's a steal, at USD 290 it's a pass.

The 7300 MB/s sequential read and 6300 MB/s write put this drive in the top tier of PCIe 4.0 drives, right up there with the Samsung 990 PRO and WD_BLACK SN850X. What surprised us is the random performance. 800K random read IOPS and 1100K random write IOPS land it in the 93rd percentile for random performance, which is wild for a DRAM-less drive. SanDisk's nCache 4.0 controller is clearly doing some heavy lifting here. The 600 TBW endurance rating is also a standout, 88th percentile, meaning this drive should outlast most of its competitors under heavy write loads. One owner mentioned transferring 1GB in about 3 seconds during backups, which tracks with the sequential numbers.

The obvious comparison is the Samsung 990 PRO, which is the gold standard for PCIe 4.0 drives. The 990 PRO has DRAM, slightly better sustained performance, and a massive reputation. But the Optimus GX PRO 850X matches it on sequential reads and actually beats it on endurance at 600 TBW versus 600 TBW for the 990 PRO 1TB, so it's a wash there. The Crucial T700 is a PCIe 5.0 drive that's faster on paper, but you'll pay a premium and need a PCIe 5.0 motherboard to see the benefit. The WD_BLACK SN850X is the closest real competitor, with similar speeds and a DRAM cache, but it's usually priced higher. If you're on a budget and don't need the absolute peak sustained performance, the SanDisk is the smarter buy. If you're doing heavy video editing or database work, the 990 PRO's DRAM cache will serve you better.

The price of this drive ranges from USD 218 to USD 290 in the US, and EUR 277 to EUR 306 in Europe. That's a USD 72 spread, which is significant. At USD 218, it's a great deal. At USD 290, you're paying Samsung 990 PRO money for a DRAM-less drive, and that's a harder sell. The best US deal we found is at Newegg, where the S3-M variant is listed at the lower end of that range. If you can get it for under USD 240, it's an easy choice. Above USD 260, you should consider the 990 PRO instead.

The SanDisk Optimus GX PRO 850X is a weird one. On paper it's a 7300 MB/s PCIe 4.0 drive with DRAM-less architecture, which usually makes us nervous. But the numbers don't lie, and neither do the owners. This thing punches way above its weight class for a DRAM-less drive, and the 600 TBW endurance rating is genuinely impressive for a 1TB TLC drive. The one thing to know? It's fast, it's reliable, and it's probably not the drive you were planning to buy, but it might be the one you should.

If you're building a portable external SSD or need a drive for a laptop that gets bounced around, this isn't it. The portable use case scored a dismal 18/100, and there are better options for that specific need. If you're doing heavy sustained write workloads like 8K video editing or running a database server, the DRAM-less design will eventually show its limits. Go get a Samsung 990 PRO or WD_BLACK SN850X instead. And if you're on a strict budget, the Kingston Fury Renegade often goes on sale for less.

The SanDisk Optimus GX PRO 850X is a genuinely great drive that's being held back by a confusing name and a lack of marketing push. The performance is there, the endurance is there, and the warranty is there. The DRAM-less design is a concern for sustained workloads, but for gaming, everyday use, and even backup tasks, it's more than enough. At the right price, this is one of the best value PCIe 4.0 drives on the market. Buy it if you find it under USD 250. If it's over USD 270, get the Samsung 990 PRO instead.