The cards you reference are not really the same thing. They are doing lookaside acceleration, where the card has to transfer the data from host memory, encrypt

The cards you reference are not really the same thing. They are doing lookaside acceleration, where the card has to transfer the data from host memory, encrypt it, and transfer it back. The Mellanox (and Chelsio) NICs do in-line crypto. They DMA down the network packets as they would have to do anyway in order to send them. Then they encrypt them on their way out onto the wire. This reduces memory bandwidth requirements by roughly 50%.