@Legit Reviews:
Crucial is only really touting sequential read/write speeds in their specifications and for that you get 2300 MB/s read and 940 MB/s on the 500GB model and 2100 MB/s read and 1140 MB/s write on the 250GB drive. (...) While the Crucial P2 SSD currently relies on Micron TLC 3D NAND technology and over time Crucial stated that it may use Micron’s QLC NAND Flash on this series and rated it as such already. We believe the transition to QLC NAND Flash will happen rather quickly on the 500GB P2 NVMe SSD and that is why the sequential write speed is rated lower.
Benchmark Results (CrystalDiskMark): (...) The larger Crucial P2 500GB drive managed to reach 2,328 MB/s read and 1,846 MB/s write. This 500GB capacity model is rated at 2,300 MB/s read and just 940 MB/s write. We are able to do just better on the sequential read side, but are nearly doubling the performance on the sequential write side.
That said, remember the Crucial P2 500GB drives being tested is using TLC NAND and not the QLC NAND that the speed ratings are based off of.