AES-NI Performance Analyzed; Limited To 32nm Core i5 CPUs

Benchmark Results: SiSoftware Sandra 2009 SP3

The ALU and MFLOPS benchmarks don’t return surprising results. The quad-core is almost twice as fast due to threading optimizations, despite its lower clock speed—as expected.

The encryption score is entirely different. This overall result says that the Clarkdale-based Core i5 with AES acceleration is nearly three times faster than a Core i7-870 quad-core.

This is why the encryption score looks so great. Plain AES-256 encryption is more than six times faster on the hardware-accelerated dual-core processor.

The SHA-256 encryption test proves that the feature only accelerates AES.

Of course, the Lynnfield design sports an on-die memory controller, while Clarkdale's memory controller is on-package, on the 45nm graphics core. As a result, its memory bandwidth is markedly lower.