When it comes to the SSDs that Apple crams inside the MacBook Air notebooks the SSDs come from one of two sources - Samsung or Toshiba. Apparently, both brands of SSDs are used inside the machines depending on what is on hand. The thing that consumers take note of when shopping is that the Samsung model SSDs are considerably faster than the Toshiba brand.
That difference in speed between the two SSD brands commonly used inside the Air may be even more noticeable this year. According to 9to5Mac, Samsung has discontinued the SSD that it was providing Apple in large quantities. The SSD was the 470, the new SSD that will take its place is called the 830, and it is considerably faster than the old 470 series. The 830 SSDs have typical speeds of 400MB/s write and 500MB/s read.
The Toshiba model that is in the Air is according to 9to5Mac capable of only a bit over 200MB/s read and 175MB/s write. That is a huge performance gap. Samsung apparently didn't confirm that it was shipping the 830 series to Apple, but if the old drives are no more and Apple keeps buying from Samsung; it will have to go with the new parts once stocks expire. Granted Apple could be sitting on a huge stockpile of 470 SSDs and could simply opt to change providers.