Crucial's new M550 SSDs are based on a new generation of Marvell controller, the 88SS9189. As usual we don't have a lot of information about the controller itself, Marvell usually doesn't share too many details about their controllers. One thing is clear however, as with their other controllers the manufacturer of the SSD has to develop their own firmware. This means that the performance can vary significantly between SSDs with the same controller.

In addition to the Marvell controller the M550 SSDs are equiped with Micron's newest generation of 20nm MLC flash-memory. In the 512GB and 1TB models Crucial has used chips with 128 Gigabit per die, similar to the M500 SSDs. In the M500 however this caused some performance loss in the 240GB and 120GB models and for this reason Crucial has chosen to go back to 64 Gigabit per die for these.