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Crucial's P1 500-GB QLC NVMe SSD reviewed

Quad damage

Just a few days ago, we reviewed a quad-level-cell SSD for the first time ever. The experience left us wanting more. Not more QLC, to be clear. We want more of the comforting, familiar march of virtually indistinguishable drives based on various manufacturers' 3D TLC NAND that we'd been living through till recently. Soon, we may be looking back on those days wistfully. But you can't always get what you want, so today we've got another QLC drive on hand. Meet Crucial's P1 500 GB.

Crucial P1
Capacity Max sequential (MB/s) Max random (IOps)
Read Write Read Write
500 GB 1900 950 90K 220K
1 TB 2000 1700 170K 240K
2 TB 2000 1750 250K 250K

The 860 QVO's role was cut and dried: to offer a sort of middle ground between smaller, faster SSDs and larger, cheaper mechanical storage. With time (and some heavy price cuts), drives like it could conceivably displace mechanical storage entirely. But unlike the QVO, the P1 isn't a 2.5" SATA drive. It's a modern, NVMe-enabled, M.2 gumstick ready to monopolize four of your precious PCIe lanes, and in fact, it's Crucial's first NVMe SSD ever.

The NVMe badge usually goes hand-in-hand with a higher set of performance expectations than average, but our experience with Samsung's 860 QVO might leave one wondering why anybody would bother producing a PCIe drive bottlenecked by dense, slow QLC NAND. The answer, as always, is caching. QLC's raw speeds are indeed too low to take advantage of all that juicy bandwidth, but toss in some sophisticated pseudo-SLC capabilities and you might just have something worth sacrificing an M.2 slot for.

The version of Crucial's Dynamic Write Acceleration implemented in the P1 uses the typical sort of static buffer allocation that all sorts of drives use as a baseline, but Crucial's tech can also commandeer up to 14% of a P1 drive's total capacity if the user has the space free. If this sounds familiar, that's because it's basically the same scheme as the Intelligent TurboWrite system we were just talking about in the 860 QVO. It wasn't enough to save the QVO from low placement in our rankings, but maybe Crucial's flavor will fare better.

Two packages of Micron's 64-layer 3D QLC flash lie under the P1's sticker, alongside a DRAM cache and Silicon Motion's SM2263 controller. The SM2263 is only a four-channel controller, and that could be the first signal that Micron doesn't expect this drive to beat any records. Even many affordable SATA drives can make good use of eight channels. The underside of the PCB is bare aside from regions marked off for two more packages and another slice of DRAM. Presumably the higher-capacity P1s make use of this space. Incidentally, this combination of NAND and controller is the exact same as that in the Intel 660p, which holds the possibly dubious honor of being the first consumer QLC drive to hit the market.

In spite of QLC's disadvantages, Micron is bullish on the durability of the P1. It backs the drive with the same five-year warranty that the company extends to its MX500 series. The endurance rating for the 500 GB drive is a solid 100 terabytes written, which is down less than you might expect from the MX500 500 GB's 180 TBW.

The P1 500 GB is available from Newegg, Amazon, or directly from Crucial's website for $110. That's fairly inexpensive, but as we saw with the QVO, cheap QLC isn't too compelling when there's cheaper TLC to be had. But we can't assume the P1 will turn in the same lackluster showing in our test suite that the 860 QVO did. Time to dust off IOMeter and see what Micron's 3D QLC can do.