M3 MacBook Air refresh boosts storage speeds for 256GB models

When Apple upgraded its Macs with the M2 chip, some users noticed that storage speeds were actually quite a bit lower than they were in the M1 versions. Both the 256GB M2 MacBook Air and the 512GB M2 MacBook Pro had their storage speeds roughly halved compared to M1 Macs with the same storage capacities.

Teardowns revealed that this was because Apple was using fewer physical flash memory chips to provide the same amount of storage. Modern SSDs achieve their high speeds partly by reading from and writing to multiple NAND flash chips simultaneously, a process called "interleaving." When there's only one flash chip to access, speeds go down.

Early teardowns of the M3 MacBook Air suggest that Apple may have reversed course here, at least for some Airs. The Max Tech YouTube channel took a 256GB M3 Air apart, showing a pair of 128GB NAND flash chips rather than the single 256GB chip that the M2 Air used. BlackMagic Disk Speed Test performance increases accordingly; read and write speeds for the 256GB M2 Air come in at around 1,600 MB/s, while the M3 Air has read speeds of roughly 2,900 MB/s and write speeds of about 2,100 MB/s. That's roughly in line with the M1 Air's performance.