Western Digital WD Blue SN5100 4TB PCIe 4.0 x4 NVMe M.2 2280

The WD Blue SN5100 is a 4TB PCIe 4.0 NVMe drive with excellent random performance and strong sequential speeds. It's built on QLC NAND, so sustained writes can slow down, but the 1,200 TBW endurance and 5-year warranty are reassuring. Pricing varies wildly, from CAD 750 to CAD 2,060 in Canada and EUR 560 to EUR 647 in Europe, so shop around. Best for laptop users who need maximum capacity in a single slot.

Let's talk about those headline numbers. 6,900 MB/s sequential read and 6,700 MB/s write put this drive in the 85th percentile for speed, which translates to 'one of the better PCIe 4.0 drives out there' in plain English. You won't see PCIe 5.0 territory here, but for real-world use, the difference between 6,900 and 7,100 MB/s is basically invisible. Game load times, file transfers, boot times, they all feel fast because you're already past the point of diminishing returns for most workloads.

The random performance is where this drive really shines. 900K random read IOPS and 1,100K random write IOPS are excellent numbers, and that 95th percentile ranking for random performance means this drive handles the kind of small, scattered file operations that make up most of what you actually do on a computer. Opening apps, browsing with dozens of tabs, loading into a game with lots of small assets, all of that benefits from strong random IOPS. The QLC NAND is the trade-off though. Under heavy sustained writes, like copying a few hundred gigabytes in one go, you'll likely see speeds drop once the cache is exhausted. For most people, that's a rare scenario, but if you're constantly moving massive video files around, it's worth knowing.

The SN5100's main competition comes from the Crucial T500, Kingston FURY Renegade G5, and Samsung 9100 PRO. The Crucial T500 is probably the most direct rival. It's typically cheaper, uses TLC NAND instead of QLC, and delivers similar PCIe 4.0 speeds. The trade-off is that the T500's random performance doesn't quite match the SN5100's 900K read IOPS, and you might not find it in 4TB as readily. If you're doing heavy sustained writes, the T500's TLC NAND will hold up better over long transfers.

The Kingston FURY Renegade G5 is another strong option, especially if you're gaming. It tends to offer excellent sustained performance and often comes in at a lower price point than the SN5100. The Samsung 9100 PRO is the wildcard here. It's a PCIe 5.0 drive, so it's significantly faster on paper, but you'll pay a premium and need a compatible motherboard to actually benefit. For most people on PCIe 4.0 systems, the SN5100's real-world performance is close enough that the Samsung's extra speed won't matter much. The Seagate FireCuda 530R and Lexar NM1090 PRO round out the field, with the Seagate offering better sustained write performance and the Lexar being a budget-oriented alternative that gives up some random performance.

Here's where things get interesting. The SN5100's affordability score sits in the 17th percentile, which means it's pricier than most drives in this category. But the value story depends heavily on where you buy it. In Canada, prices range from CAD 750 to CAD 2,060 across four listings. That's a CAD 1,310 spread for the exact same drive, which is frankly absurd. Memory Express has the best deal at CAD 750, and if you're paying anywhere near CAD 2,060, you're getting taken for a ride. In Europe, the spread is tighter but still notable, from EUR 560 to EUR 647 across four listings. The EUR 560 price is the one to look for.

For the US market, you're looking at USD 520 from a single listing, and in the UK it's GBP 484. Compared to the competition, the SN5100 is generally more expensive than drives like the Crucial T500 or Kingston FURY Renegade G5 at similar capacities, but you're paying for that 4TB capacity and the strong random performance. If you can find it at the lower end of those price ranges, it's a reasonable deal. At the high end, you're better off looking elsewhere.

The WD Blue SN5100 is one of those drives that makes you do a double take. It's a 4TB NVMe SSD with PCIe 4.0 speeds that lands in the top tier of our database for random performance, yet it's built on QLC NAND, which usually means compromises. Western Digital is positioning this as a high-capacity workhorse for laptops and desktops, and honestly, the numbers back that up for the most part. You get 6,900 MB/s reads and 6,700 MB/s writes, which is right up there with drives costing a lot more.

Who's this for? If you're the type who keeps a massive Steam library, edits large photo batches, or just hates uninstalling things to make room, the 4TB capacity is the headline here. It sits in the 93rd percentile for capacity, which means you're getting more room than almost anything else in this category. And the random read performance at 900K IOPS is genuinely best-in-class territory, landing in the 95th percentile. That's the kind of spec that makes everyday tasks feel snappy even when the drive is half full.

The catch is that QLC NAND and a 17th percentile affordability score tell you this isn't a budget play. QLC drives tend to slow down under sustained writes once the SLC cache fills up, and while Western Digital's nCache 4.0 helps, it's not magic. Still, with a 1,200 TBW endurance rating and a 5-year warranty, WD is standing behind this drive more than most QLC offerings. That's a signal worth paying attention to.

If you're doing heavy sustained writes on a regular basis, like editing 4K video or running a database server, the QLC NAND in the SN5100 will eventually slow down on you. The cache fills up and write speeds drop, sometimes significantly. You'd be better off with a TLC drive like the Crucial T500 or the Seagate FireCuda 530R, both of which handle sustained writes more gracefully. The FireCuda 530R in particular is known for strong sustained performance.

Also skip this if you're on a tight budget. The 17th percentile affordability score means you're paying a premium for the 4TB capacity and strong random performance. If you don't need 4TB, a 2TB TLC drive will cost less and give you better sustained write performance. And if you're building a portable external drive, look elsewhere. The portable use case score of 20.7 out of 100 is one of the weakest we've seen, likely due to power draw and thermal considerations that make it a poor fit for bus-powered enclosures.

If you need 4TB of fast storage in a single M.2 slot and you're not doing massive sustained writes every day, the SN5100 is a compelling choice. The random performance is genuinely excellent, the sequential speeds are more than enough for PCIe 4.0 systems, and the 5-year warranty with 1,200 TBW endurance gives you peace of mind. Laptop users score it 81.4 out of 100 in our database, which makes sense given the capacity and efficiency. It's a great fit for a laptop that only has one M.2 slot and needs to hold everything.

For gamers, the 74.1 out of 100 score is decent but not outstanding. Game load times will be fast, but you're paying a premium for capacity that many gamers don't strictly need. If you're building a desktop with multiple M.2 slots, you might be better off with a smaller, cheaper TLC drive for your OS and a separate high-capacity drive for storage. The SN5100 makes the most sense when you need both speed and capacity in a single drive, like in a laptop or a small form factor build.