Bit rot on SSDs

porina · September 28, 2021

Today I dusted off a system to prepare it as my Win11 test machine. The current SSD in it is a cheap Kingston A400. These are amongst the lowest cost branded SSDs. Without checking, I assume it is DRAM-less, and to get the price down, I wonder if they use lower grade flash too. Using the existing Win10 install on it, I saw disk usage go to 100% as the system became unresponsive. That to me is suggestive of the storage going bad. To cut the story short, SMART reported something like 7 bad sectors and 5 reallocated sectors.

In searching around I found a suggestion to run HD Tune to do a surface scan. It found and marked one block as bad. At this point I didn't want to spend more time on that install. I'm doing a fresh install on a NVMe SSD which should give better performance anyway. Kingston's SSD tool didn't report any problems with that SSD.

I know it is not an unexpected thing for areas to degrade over time, but the expectation is it can be managed by the drive before user data is lost. Also this isn't the first time it happened. I don't recall exactly what model I saw similar on, it was also a budget branded SATA SSD. Wipe and reinstall, all was fine. It's like the data is rotting faster than the ECC in drive can cope with. Maybe power on time helps? Maybe not. More drive usage, and thus, more chance for files to get re-written, might also help prevent it.

Out of curiosity, I also ran HD Tune on my oldest still used SSD. A 512GB Samsung SM951 from 2015. No problems detected.

While I might have more SSDs than average, it probably isn't a big enough sample to go on. Still, it does seem to me that cheap SSDs may lose data integrity over time.