Guidance Change: Calculating the Megacycles for Different Processor Configurations

The guys at MS Exchange Team have released a guidance change on the formula to calculate the megacycles for different processor configurations. Their new guidence is published here and is available for viewing.
Recently we made a change with respect to how we normalize the available megacycles of server platforms with respect to our baseline system.  Initially, we adjusted megacycles per core with respect to the total megacycles of the system and derived this formula:
((New platform per core value) * (Hertz per core of new platform)) / (Baseline per core value) = Adjusted Megacycles per Core
However, that is not the correct way to look at normalizing the server platforms against our baseline. What we are actually interested in is how this impacts the active mailbox user count.  Therefore the new formula is:
((New platform per core value) * (Hertz per core of baseline platform)) / (Baseline per core value) = Adjusted Megacycles per Core
This guidance change is effectively immediately and is documented within the TechNet article, Mailbox Server Processor Capacity Planning.  The documentation within the Exchange 2010 Mailbox Role Requirements Calculator will also be updated to reflect this.
Don't panic if you used the old calculations, the team say that you will simply end up with a little extra megacycle capacity. In these days with such tight budgets that may not be a terrible thing to have at the offset, especially as we know how quickly mail platforms become underpowered... You can read their full explanation here.