I can't say offhand, since I don't have much experience with storage. I'd expect that most of the work from a SSD read is offloaded to the disk controller, whi

I can't say offhand, since I don't have much experience with storage. I'd expect that most of the work from a SSD read is offloaded to the disk controller, which presumably uses DMA, and you don't have nearly as many round trips (a sequential read can be done with a single SCSI command). I'm inclined to agree with the explanation given by other commenters that the limiting factor for SSD r/w speeds in the cloud is due to throttling in the hypervisor to provide users with predictable performance as well as isolation in a multitenant environment.