As you may know, recent Intel processors have an extension to the x86 instruction set called Advanced Encryption Standard Instruction Set (AES-NI).
AES-NI is basically hardware support for AES based encryption and because I had a chance to run some benchmarks on differing systems I was curious what the impact of AES-NI would be.
I used TrueCrypt for running the benchmarks because this is a real life application and it has support for AES-NI.
I first ran the benchmark on a laptop with an Intel Core2 DUO (P9700 2,80 GHz):
The next system was an Intel Core i7 Q740 (Quad Core with Hyperthreading, so 8 in total) machine.
This is a real fast machine, and the Processor score confirms this:
So I was expecting a huge performance increase in the benchmarks but it’s only slightly faster:
The reason is that unlike most other i7 CPU’s the Quadcore (mobile) CPU’s do not have AES-NI support.
The big surprise was the benchmark on a machine that was in theory slower but did have AES-NI support. It had an i7-640M CPU (Dual Core with HyperThreading):
That’s an impressive difference (around 5 times faster on AES)!
So my conclusion is that if you use Encryption software a lot (eg if you use software based Drive Encryption) an AES-NI enabled CPU is preferred.
Intel publishes a list of AES-NI enabled CPU’s here.