[salicideblock]

Expanding on this,a very nice property of Galois Counter Mode (GCM) for AES is that encrypting one block does not require the previous block to be encrypted, like in AES-CBC.

This means that AES-GCM can take advantage of data parallelism and there are big speedups in threaded and pipelined CPUs.

In short, you can get big latency and throughout gains by using AES-GCM over AES-CBC.