I recently saw a link on Twitter to a blog post on The Practice of Code where Jay nicely details the performance difference between his 2010 MacBook Air 11”, which had a Toshiba SSD (with a 128GB capacity), and a new 2011 MacBook Air 11” fully-upgraded to the i7 processor, 4 GB of memory, etc. which happened to come with the Samsung SSD (256GB in this case). He shows a graph comparing these two machines’ disk scores from XBench both with and without Lion’s FileVault whole-disk encryption turned on.
Well, I also have a new i7 MacBook Air (in my case with the 13” screen size but otherwise configured the same as Jay’s), and I’d been considering turning whole-disk encryption on, so this post was timely.
In my case, I had the “bad fortune” to end up with a Toshiba 256GB SSD in my Air (again — my 2010 Air also had a Toshiba drive). Apple appears to source their SSD drives from either vendor at random, and it has been known for a while that the Samsung drives are somewhat faster than the Toshiba ones.
However, this did provide me with an opportunity to run the tests Jay described on my Toshiba drive and get some numbers that I could compare with his Samsung. Adding my numbers to the ones he gave in his post produces the following:
So the Toshiba drive is in fact somewhat slower than the Samsung, but not by too large a margin. In the sequential and overall cases, it’s almost as fast as the Samsung drive even though it falls behind a bit more in the random access tests.
Also, the 256GB Toshiba in the 2011 Air is faster than the 128GB Toshiba in the 2010 Air by a noticeable amount (I don’t know if this is due to the capacity — perhaps the 2010 Air with a 256GB drive would have been as fast in the non-FileVault case? — or due to a newer model of the Toshiba drive perhaps being used now).
The overhead added by FileVault is similar regardless of drive vendor, as one might expect since the processor doing the work is the same in both of the 2011 cases.
As I’ve used them, I’ve never noticed the Toshiba SSDs feeling slow. Regardless of brand, an SSD holds clear advantages over a spinning-disk-based drive, so I’m happy to have one in my laptop. Still, it’s nice to know that I’m not sacrificing too much performance due to the make of drive my machine happens to contain, and it’s also good to be aware of the overhead FileVault incurs.