SSD & Disk Encryption

What impact does encryption have on an SSD?

I’ve recently picked up a 13” Macbook Pro Retina to act as my travel buddy - and as I’m out and about with it I wanted to do the sensible thing and ensure all the data on the internal SSD hard drive was encrypted. Encryption and SSDs has an interesting history - when I first started using SSDs a number of years ago, and full disk encryption, the units suffered badly from write-fatigue.

From what I can tell now however this doesn’t appear to be the case. There is a minor impact on performance, but certainly not noticeable.

Let’s have a look at the performance when the SSD is
not encrypted - pretty good throughput on the PCI bus:


Next, I turned on
File Vault and let it finishing encrypting the drive - then, I re-ran the performance tests. Here’s the results:


So the averages impact turned out to be circa 4% on reads, and 2.5% on writes. That’s not too shabby I don’t think, and on that basis I’ll happily ensure my File Vault is enabled.

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