I wanted to point you to a paper we just published today exploring the difference in resource utilization (ie. time, processing cycles) between SHA256 and MD5. The paper, titled "What’s the Real Impact of SHA-256?", can be found at the following link along with the scripts used for testing and the raw data from the test results. http://www.avpreserve.com/avpsresources/papers-and-presentations/
All feedback and thoughts are welcome.