(or, at least, faster than some of my servers)
I ran some openssl speed tests today, to figure out the speed difference between AES-128 and AES-256 on multiple platforms, with and without hardware acceleration (AES-NI). AES-256 is 25% slower than AES-128 on average. If you're interested, the discussion goes on the dev-tech-crypto mailing list at https://groups.google.com/d/msg/mozilla.dev.tech.crypto/36na1B2brGU/xUMMPMgkmEMJ
But more interestingly, I ran some openssl tests on android, on my Galaxy S3 equipped with an ARMv7 (1.5GHz Dual Core Qualcomm MSM8900). And it does AES faster than 3 small servers I own. One is a Dedibox from french hosting company online.fr, that run on a VIA cpu. The second one is an AWS EC2.Medium, that exposes an AMD Opteron. And the third one is a home server that runs on Intel Atom D510.
The block size matters, but the gist of it is, the ARMv7 is at least as fast than any of the other three, and sometimes up to 50% faster.
The full table is here: http://jve.linuxwall.info/ressources/taf/aesmeasurements.txt
Of course, compared to the Intel Core i7 that equips my laptop, which supports AES-NI and can encrypt ~620MB/s, the ARM is far behind. But with a bandwidth of 68MB/s, the days of slow crypto on cellphones are over. And this is an excellent news!