The Sabrent Rocket Q4 is one of only a few QLC-based PCIe 4.0 SSDs on the market. Actually, there are only two: the Corsair MP600 Core and Sabrent Rocket Q4. The PCIe Gen 4 interface promises twice the throughput of Gen 3, so SSD makers exploring all possible options is only natural. Internally, the Sabrent Rocket Q4 is based on the combination of 96-layer QLC flash from Micron paired with the Phison E16 controller, plus 2 GB of DRAM cache.

Synthetic numbers of the Sabrent Rocket Q4 are very impressive. Especially random IO, both read and write, and sequential transfers are mighty impressive. If our review stopped here, we'd conclude that the Sabrent Rocket Q4 is a high-performing Gen 4 SSD that offers performance rivaling the latest Gen 4 TLC drives, at much better pricing.

Our real-life testing suite goes beyond synthetics and runs the actual applications at 80% disk full, which is a more realistic scenario than a completely empty drive running a synthetic test. Real-life benchmarks are much harder to optimize for, too. Here, the Rocket Q4 shows much weaker numbers that are surprisingly low. When averaged over all our tests, the Q4 matches PCIe 3.0 mid-range drives like the Kingston A2000 and Samsung 970 EVO. High-end Gen 3 drives like the ADATA SX8200 Pro, Kingston KC2000, HP EX950, and Hynix Gold P31 are between 6 and 9% faster—not that much, but still significant. On the other hand, if you know your workload consists of lots of large transfers, like when copying huge files, the Rocket Q4 will definitely shine because of the PCIe 4.0 interface. For example, in our ISO file copy test, the Rocket Q4 is the fifth-fastest drive we ever tested—pretty nice. Looking back at averages, the fastest PCIe 4.0 drives—Samsung 980 Pro and WD Black SN850—are up to 13% faster, at much higher pricing.

Sequential write performance of the Sabrent Rocket Q4 starts out fantastic. While writing to pseudo-SLC cache, the transfers complete at impressive 3.5 GB/s and are sustained for very long. Actually, the Q4 will fill its whole capacity with SLC data first, and only then start writing to QLC directly. In this state, write speeds are down by more than 90%, reaching around 250 MB/s only. Of course, momentarily stopping the write activity will have the SLC cache free up capacity immediately, so full write rates are available as soon as you give the drive a moment to settle down.

Sabrent is bundling a pretty nice heatsink with the Rocket Q. Technically, the bundle is a separate SKU that's $20 more expensive. While we saw some thermal throttling on the uncooled Rocket Q4 in our thermal stress test benchmark, adding the heatsink made sure this won't happen, or only after a really long time. I've seen many M.2 heatsinks over the past years and like Sabrent's design approach. There's plenty of material which can soak up heat, and installation is super easy. The heatsink is also compatible with any other M.2 SSD, so you can mix and match as needed.

Priced at $300 for the tested 2 TB version, the Rocket Q4 isn't exactly cheap. Now, if you compare against PCIe 4.0 TLC drives, then $300 is a bargain, of course. The Samsung 980 Pro 2 TB and WD Black SN850 are both $400. The Corsair MP600 Pro is even $430—no idea why it's so expensive. The problem is that these drives are considerably faster than the Rocket Q4 and built using TLC flash, which has better write speeds and longer endurance. Strong competition comes from the high-end PCIe 3.0 drives, too, as they are faster than the Rocket Q4 and more affordable. For example, the HP EX950 2 TB and Kingston KC2500 are $290, and the ADATA SX8200 Pro 2 TB is only $250.