Previously I looked at the then new Apple Mac laptops with Core i CPUs and their AES-NI hardware extensions. Since then I've learnt that the openssl shipping with Mac OSX Lion has not been compiled with AES-NI support.
Here's an easy way to tell. From the command line run "openssl engine"
$ openssl engine
(aesni) Intel AES-NI engine
(dynamic) Dynamic engine loading support(dynamic) Dynamic engine loading support
See the line "(aesni) Intel AES-NI engine"? if its not there, then its not happening.
And thats how I know openssl on Mac OSX Lion 10.7.4 doesn't have it.
So how to benchmark? Turns out that Truecrypt has a benchmarking engine.
1. Launch Truecrypt and click "Create Volume"
2. Then click "create an encrypted file container"
3. Give it a name, doesn't matter what and where, we'll never save it
4. Then Benchmark
5. When this screen loads, select a buffer size and press Benchmark. Try not to have any other processes eg browsers running since this will skew the results.
Here's an example - this is a Core 2 Duo at 2.26GHz
As you'd expect, huge difference!
Some more here