SanDisk 4TB SSD PCIe 4.0 x4 NVMe M.2

The SN850X 4TB hits 7,300 MB/s reads and sits in the 96th percentile for random performance, making it one of the fastest Gen4 drives on the market. Owners rate it 4.8 out of 5 stars across nearly 19,000 reviews, and the 2,400 TBW endurance means it's built to last. It's pricey at the 10th percentile for affordability, but on sale it's a steal. No heatsink included, so PS5 owners need to factor that in.

The SN850X is a monster in the numbers that actually matter for real-world use. Sequential reads hit 7,300 MB/s and writes land at 6,600 MB/s, which puts it at the 89th percentile for speed. But the real story is random performance. At 1,200K random read IOPS and 1,100K random write IOPS, this drive sits in the 96th percentile, which is the absolute best right now for Gen4 drives. That translates to snappy game loads, fast file transfers, and a system that never feels like it's waiting on storage. The TLC NAND paired with DRAM cache and WD's in-house controller keeps things consistent even when the drive is mostly full, which is where cheaper DRAM-less drives fall apart.

For gaming, the 92.7 out of 100 score in our database backs up what owners report. Multiple reviews mention hitting 7,133 MB/s read in performance mode, which is close enough to the rated spec that we're not complaining. The drive is also backward compatible with PCIe 3.0, so older systems still get a meaningful upgrade even if they can't tap the full Gen4 bandwidth. The one thing to keep in mind is thermals. Without a heatsink, sustained heavy writes can push the controller into thermal throttling territory. It's not a dealbreaker for most users, but if you're doing massive file transfers regularly, grab a heatsink or make sure your motherboard has one built in.

Against the Samsung 9100 PRO, the SN850X holds its own on random performance while often undercutting Samsung on price when sales hit. The Kingston FURY Renegade SFYRDK/4000G is a closer match on specs, but the SN850X edges it out in our random performance rankings. The Crucial T500 and Micron T710 are solid alternatives, but neither matches the SN850X's combination of 4TB capacity, DRAM cache, and that 96th percentile random performance. Where the SN850X loses ground is on price. The Samsung 9100 PRO is also expensive, but Samsung's brand tax is baked in. The SN850X feels like it should be cheaper than it is, especially when you factor in the missing heatsink. If you're building a PS5 expansion, the lack of a heatsink means you're adding another USD 10 to USD 20 on top of the drive cost, which narrows the gap with competitors that include one.

Here's where things get interesting. The SN850X 4TB is not cheap, and our database puts it at the 10th percentile for affordability. That's a polite way of saying it's one of the most expensive drives in its class. But the price spread across vendors is wild. In the US, we're seeing listings from USD 600 to USD 1,099, which is a USD 499 gap for the exact same drive. If you're shopping in the US, the lower end of that range is where this drive becomes a no-brainer. In Canada, the spread is tighter at CAD 900 to CAD 1,000, so you're not saving much by hunting around. The real value play here is waiting for a sale. Owners consistently mention that this drive is excellent value when discounted, and given the 2,400 TBW endurance and top-tier performance, it's hard to disagree. Just don't pay the top of that USD range unless you enjoy lighting money on fire.

The WD_BLACK SN850X 4TB is one of those drives that makes you wonder why you'd spend more on anything else. Our database puts it at the 96th percentile for random performance and the 93rd for capacity, which means it's not just fast, it's fast while holding an absurd amount of stuff. The 7,300 MB/s read and 6,600 MB/s write speeds are basically the ceiling for PCIe 4.0, and the 1,200K random read IOPS put it in the absolute top tier of Gen4 drives we've tracked. Owners agree, with a 4.8 out of 5 rating across nearly 19,000 reviews and a sentiment score of 92 out of 100. The recurring theme? Blazing speed, great value, and a drive that just works.

But it's not all sunshine. The affordability ranking is a rough 10th percentile, which means you're paying a premium for that 4TB capacity. And while the drive itself is excellent, the lack of an included heatsink is a real annoyance for PS5 owners who need one for the expansion slot. Still, when this thing goes on sale, it's hard to argue with the price-to-performance ratio. The 2,400 TBW endurance rating and 5-year warranty mean you can hammer this drive with writes for years without sweating it.

If you're building a portable rig or need something for an external enclosure, look elsewhere. The portable use case scores just 23.7 out of 100 in our database, which is one of the worst we've seen for that scenario. The drive runs hot under sustained load, and without a heatsink it's not ideal for tight enclosures. Also, if you're on a strict budget, the 10th percentile affordability ranking means this drive will hurt your wallet. There are cheaper 4TB Gen4 options that sacrifice some random performance but cost significantly less. And if you're already on a Gen5 platform, you might want to hold out for a Gen5 drive that can actually use that bandwidth instead of paying a premium for a Gen4 drive that's already maxed out.

The WD_BLACK SN850X 4TB is the drive to beat for anyone who wants top-tier Gen4 performance without jumping to Gen5 pricing. The 96th percentile random performance and 7,300 MB/s sequential reads put it in the absolute best tier of drives we've tested, and the 2,400 TBW endurance means it'll outlast most builds. The 4.8-star rating from nearly 19,000 owners isn't a fluke. This drive delivers. The only real knock is the price, which sits at the 10th percentile for affordability. But if you catch it on sale, especially at the lower end of that USD 600 to USD 1,099 range, it's one of the best storage purchases you can make right now. Just budget for a heatsink if you're dropping it in a PS5.