Something New: Cryptography Support
The developers barely made any micro architectural changes to the cores of the new Clarkdale processors compared against those of Lynnfield. In fact, this is the essence of the “tick tock” concept: if the manufacturing process is improved the microarchitecture remained untouched. But nevertheless, Intel couldn’t help it and added one small but important detail to their new Clarkdale CPU. This processor supports a few new instructions – AESNI set. This set includes six new instructions that accelerate the work of cryptographic AES algorithm, which is one of the most widely spread algorithm for block encryption used by numerous applications.
Here it is important to keep in mind that AESNI support is not activated in all Clarkdale processors, but only in those modifications that belong to the “top” Core i5-600 series. Core i3 and Pentium processors do not have any hardware support for cryptographic algorithms yet. This gives us the opportunity to estimate the encryption speed improvement on processors with AESNI support.
For example, we resorted to Sandra utility featuring a cryptographic benchmark to get an idea of AESNI operation. We checked out the results in an LGA1156 platform with Core i3 and Core i5 processors working at the same clock frequency of 3.06 GHz.
As we see, the CPU with AESNI support performs encryption an order faster than its counterpart without this support. But as you can clearly notice, this effect only takes place during AES encryption. Another cryptographic test measuring the hashing speed using SHA256 algorithm is performed equally fast on both processors, which is quite logical since the instructions from the AESNI set are utilitarian and can only be used during AES algorithm utilization.
Introduction of AESNI instructions support is dramatically different from the traditionally painful adoption of every new SSE extension. Things are absolutely the opposite this time because new instructions are supported not only in specifically optimized synthetic tests. The AESNI set is very up-to-date that is why many popular application developers have already implemented it in their solutions. For example, it already exists in some archiving tools that not only compress data but also encrypt them. As an example of a program like that Intel recommends WinZIP, which 14th version uses AESNI, but we decided to check how the new instructions are supported using another freeware archiving application 7-zip 9.10.
We do see some acceleration, but it is not as impressive as in the synthetic test. In fact it is absolutely correct: against the background of other algorithms that compress the data, the gain from fast encryption gets a little lost. However, we can’t deny that it is indeed there.
Another pleasing fact is that AESNI is also available in Windows 7. All programs using standard functions from the Cryptography API: Next Generation (CNG) included with this operating system will enjoy higher performance on Clarkdale processors supporting the new instructions set without any modifications necessary. For example, take the relatively old PCMark Vantage test, namely the Communication pattern, which uses CNG functions for encryption and decryption algorithms.
As a result, we see that despite the absence of obvious AESNI support in PCMark Vantage, it runs way faster on a system with a CPU supporting this instruction set.