SSHD will function as normal Hard Drive when the SSD Cache wear out

For SSHD users, we do worry about what happen when the SSD Cache wear out. Toshiba does provide official information on their SSHD FAQ.

I have heard that NAND flash can wear out over time. What happens if the NAND component in the Toshiba SSHD reaches its endurance limit? Will data be lost?

Should the user exceed the endurance limit of the NAND flash, the Toshiba SSHD will continue functioning as a conventional HDD. However, before the NAND flash component reaches the endurance limits, its performance will gradually decline. Due to Toshiba’s NAND flash caching algorithms and data protection mechanisms, Toshiba does not expect an increased risk of data loss resulting from aging of the NAND flash on the Toshiba SSHD during the expected lifetime of a PC.

But I cannot find any similar information from Seagate, I have no proof to know it’s the same to Seagate SSHD.

SSD cache in SSHD compromises the lifecycle compared to standard HDD? on superuser provides a good discussion on this topic.

My conclusion: before the SSD cache wear out, there will be more and more damaged chips in SSD which means the available SSD cache is becoming smaller and smaller. User shall notice that the performance is decline slowly without any warning from S.M.A.R.T. .


  1. Toshiba
  2. Toshiba: Solid State Hybrid Drive (SSHD) – SSHD FAQ
  3. Seagate
  4. superuser: SSD cache in SSHD compromises the lifecycle compared to standard HDD?
  5. superuser
  6. StorageSearch: SSD endurance – the forever war
  7. Wiki: S.M.A.R.T.

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