This series uses a custom PCIe 2.0 x4 SSD. While you bought your system in 2017 it is the exact same hardware as the Early 2015 with just a slightly goosed up CPU. As far as upgrading the SSD here is the IFIXIT guide you'll need to follow: MacBook Air 13" Early 2015 SSD Replacement and here is another option: Transcend - JetDrive 820. Shop Apple MacBook Air 13.3" Certified Refurbished Intel Core i5 with 4GB Memory 256GB Flash Storage SSD (2015) Silver at Best Buy. Find low everyday prices and buy online for delivery or in-store pick-up. Price Match Guarantee. Reconnect the power cord and all other cables to the computer, then start up the computer. Your iMac performs a memory initialization procedure when you first turn it on after upgrading memory or rearranging DIMMs. This process can take 30 seconds or more, and the display of your iMac remains dark until it's finished. New 11-inch MacBook Air (early 2015) review: Specs. Top sequential speed from the SSD reached 754 MB/s for reads, and 316 MB/s for writes, the former figure especially entirely unheard of from O2Qr.