4TB Crucial P3 Plus PCIe Gen4 M.2 Solid State Drive SSD EXPIRED

Copying a comment I made in a post about the P3 (same drive, just PCIe gen 3)...

These have no DRAM and are QLC, but use the NAND in pseudo SLC mode to cache writes. This causes a significant slow down on sustained writes, probably a non issue for most, or at least wouldn't be noticed until the drive is near full. The rated endurance could be an issue, depending on use case.

The controller stores incoming data as single bits in cells during writes, then later rewrites it as 4 bits per cell. On the 2 TB version TomsHardware saw writes slow to 100 MB/s after 550GB written - which is 50GB more than expected with pSLC caching, probably due to the controller actively converting / compressing pSLC to QLC during the sustained write. These drives give you a little more than 25% of current free space writeable at specced speed. That's probably why the TBW rating for these is comparatively low - because each write to the drive is actually multiple writes, once spread out as 1 bit per cell, then again as compressed / native 4 bits per cell. With 1 tb free you'd likely get 280 GB transferred at rated speed. With 4 tb free you'd have over 1 tb of sustained high speed writes before it drops down.

FYI, QLC and no DRAM.

If only there were some opposite action to a downvote. 🤔