I am running Windows 8.1 Pro on a Samsung 830 SSD. I do not have a TPM module so I've made the necessary configuration changes to permit BitLocker encryption of my system drive without a TPM module.

Given my configuration, will encrypting my system volume negatively impact my SSD's lifespan or speed? Are there other consequences of encrypting an SSD I should be aware of?

  • The performance is discussed there, thanks. But is there any impact on the lifespan? – blckbird Dec 1 '14 at 23:42

Impact of Bitlocker on performance of SSD

See a similar superuser question here.

Impact of Bitlocker on lifespan of SSD

Microsoft's answer to the question:

"Is Bitlocker’s encryption process optimized to work on SSDs?"

Yes, on NTFS. When Bitlocker is first configured on a partition, the entire partition is read, encrypted and written back out. As this is done, the NTFS file system will issue Trim commands to help the SSD optimise its behaviour.

From a similar superuser question:

If the disk controller does not use compression, then encryption will not change anything. If the controller uses compression then encryption will probably reduce the lifespan of the disk (compared to an identical disk where encryption is not used).

From "random" blog posts: *See conclusion.

(For Software Based Encryption eg Bitlocker):

Even when you change a single bit in file, due to the re-encryption of the file, the whole file will be written back to the SSD and not only the changed block of data. This will incur additional wear-and-tear of the SSD, reducing the performance exponentially.

You can prevent this additional reduction of performance by using Self Encrypting Drives (SED). A SED will encrypt data in the hardware of the drive. So you win on drive performance two times:

  1. Encryption is done in real-time (e.g. when SW FDE is applied it will reduce immediately 40-50% of SSD read and write performance)

  2. inefficient use of the SSD is prevented by optimization routines in the controller of the SED.

SSDs get a lot of their performance and longevity from doing extremely smart reads and writes at the block level and by compressing the data intelligently. When presented with an encrypted volume, the SSD can make no determinations about the data and has to read and write entire blocks at a time. There's typically a pretty big performance penalty as well, and it wears the drive a lot faster.


I believe that the superuser answer I linked to is more detailed, so you'd need to find out whether your SSD encrypts the data to save space, then make your decision.

As Ramhound said, "a random blog post by a random person isn't the best source of information", I think that the information provided is slightly inaccurate as it assumes that all the data is rewritten to encrypt it, while in reality there should be no need to perform extra reads or writes because the data is encrypted before being written to the platters, and decrypted before being sent to the process that performed the read.

Overall my opinion is that the security outweighs the lifespan, as you're not likely to hit the write limit on modern SSDs in a reasonable number of years.

Sources: Here, here, here and here.

  • 1
    This means you have to trust the OEM of the SSD's firmware to implement encryption. I personally place more faith in Apple, Microsoft and the open source community to implement whole-disk encryption instead of hardware companies. A random blog post by a random person isn't the best source of information. It mentions benchmarks but does not provide them, a common sign, the author doesn't have the proof to backup their statements. – Ramhound Dec 2 '14 at 0:34
  • @Ramhound edited the question. Included more reliable sources. – Rsya Studios Dec 2 '14 at 2:07
  • I appreciate you using more appropriate sources. If these software based full-disk encryption implementation actually did lower the lifespan of SSDs it would be trivial to prevent them from being used on SSD devices just like you can't even attempt to defrag a SSD without an serious effort. – Ramhound Dec 2 '14 at 2:34

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