Crucial P3 4TB PCIe Gen3 NVMe M.2 SSD (CT4000P3SSD8): specs explained

The Crucial P3 4TB (CT4000P3SSD8) is an M.2 NVMe solid state drive for desktops and laptops. It uses the PCIe Gen3 interface and offers a large 4TB capacity, so it can hold a full operating system, a games library and a large collection of photos or video in one slot. Here is what the specs mean.

What NVMe and PCIe Gen3 x4 mean

NVMe is a protocol designed for flash storage that connects directly to the processor over PCIe lanes instead of going through the older SATA interface. The P3 uses four PCIe Gen3 lanes (x4). Crucial says this gives sequential reads up to 3,500MB/s and, per its description, writes up to 3,000MB/s.

For comparison, Crucial says NVMe performance is nearly five times faster than SATA and nearly twenty times faster than a hard disk drive. Those figures are the brand's own and depend on the system, the workload and the drive's state. In general, Gen3 drives are quick for boot, loading and file copies, though newer PCIe Gen4 and Gen5 drives reach higher peaks.

Random performance

The listing gives random read and write performance as 650K and 700K IOPS. IOPS (input/output operations per second) measures how many small reads and writes the drive can handle each second. That is the sort of work an operating system does constantly when launching programs or opening many small files, so it affects how responsive a PC feels more than sequential speeds do.

4TB capacity and Micron 3D NAND

The P3 is made with Micron Advanced 3D NAND. 3D NAND stacks memory cells in layers to increase density, which is how capacities like 4TB fit on a small M.2 stick. Crucial states the drive performs up to 33% better than the previous generation.

Large capacities help in practice with big game libraries, video editing projects, virtual machines and photo archives. Keep in mind that SSDs usually perform best with some free space left over.

Reliability

Crucial lists a mean time to failure (MTTF) of more than 1.5 million hours. MTTF is a statistical figure from testing, not a prediction for a single drive. It is a useful comparison between products but no substitute for backups. Important data should always be copied elsewhere, whatever drive it lives on.

Form factor and fitting

The drive uses the M.2 format, a small stick that attaches to a slot on the motherboard or in a laptop, with no cables. Check that the slot supports NVMe, not just SATA M.2, and the right physical length. Most M.2 drives of this type are 80 mm long (the 2280 size), so confirm the length your slot supports.

Who it suits

It suits people who need a lot of fast storage without needing a newer Gen4 interface: desktop upgrades, laptops with a spare M.2 slot, content creators with large libraries and gamers with many installed titles. Because it is PCIe Gen3, it also works in newer systems; the interface is backward compatible, but speeds will be limited to Gen3 levels.

What to check before you buy

• M.2 slot type: make sure your device has an M.2 slot that supports NVMe (PCIe) and a 2280-length drive.
• Device support: check the laptop or motherboard manual for which M.2 drives and capacities are supported.
• Heatsink space: some motherboards include M.2 heatsinks; check they fit.
• Backup plan: keep copies of important files.
• Migration: decide whether you will clone your current drive or do a fresh install.

The short version

• A 4TB M.2 NVMe SSD, model CT4000P3SSD8, using PCIe Gen3 x4.
• Up to 3,500MB/s sequential reads, with random read and write of 650K and 700K IOPS.
• Micron 3D NAND, and an MTTF figure of over 1.5 million hours.
• Fits any M.2 NVMe slot; speeds are limited to Gen3 levels.

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