If I recall correctly, this has to do with how NAND flash storage stores the data on the physical media. I think trimming in SSDs performs some kind of maintenance in this regard but it all has to do with that the cells storing the bits (which make up the data) have a limited lifetime of being written to.
After a while, it will stop being able to write to specific cells in the media and the drive eventually “fails”. I think the way the drives work is they try to actively not write to the cell as often to increase the longevity of the drive. So when it gets filled up, maybe it’s trying to calculate more with less available cells? Not sure why else.
The big issue (as the article says) is that TLC/QLC drives have a faster dynamic SLC cache.
Skip this if you know what the terms mean:
SLC (Single Level Cell) means per cell there’s one bit stored
MLC (Multi Level Cell): one cell stores 2 bit
TLC (Triple Level Cell): 3 bit
QLC (Quad Level Cell): 4 bit
So the more bit per cell, the more storage the drive has, but the slower it is.
Because of that SSD controllers use part of the free space on a TLC/QLC drive in SLC mode as a fast cache, trading unused storage space for more speed.
The fuller the drive gets the smaller the cache will be, and on an almost completely full drive there is no cache.
If I recall correctly, this has to do with how NAND flash storage stores the data on the physical media. I think trimming in SSDs performs some kind of maintenance in this regard but it all has to do with that the cells storing the bits (which make up the data) have a limited lifetime of being written to.
After a while, it will stop being able to write to specific cells in the media and the drive eventually “fails”. I think the way the drives work is they try to actively not write to the cell as often to increase the longevity of the drive. So when it gets filled up, maybe it’s trying to calculate more with less available cells? Not sure why else.
The big issue (as the article says) is that TLC/QLC drives have a faster dynamic SLC cache.
Skip this if you know what the terms mean:
So the more bit per cell, the more storage the drive has, but the slower it is.
Because of that SSD controllers use part of the free space on a TLC/QLC drive in SLC mode as a fast cache, trading unused storage space for more speed.
The fuller the drive gets the smaller the cache will be, and on an almost completely full drive there is no cache.
TIL moment 😀