|The main benefit of ACMS based systems is to minimize any overhead usually attributed to processes. WIth ACMS, there will be a few processes (usually 3-8) that handle all of the work which comes from multiple sources (terminals for example). There is no specific way to get transaction level CPU usage easily. It can be done with some testing, but usually is not a meaningful metric.|
More important is whether or not the "new" system will be sufficient for the expected workload. If you are running an ACMS based application now, you would be better trying to run the current application on the new hardware (Itanium) to get a handle on the behavior changes due to hardware. Not only are Itanium systems typically faster than Alpha systems, but hte underlying architecture is different making it near impossible to make a 1-to-1 comparison about application performance without some experimentation.
The question you are asking can not be answered definitively here. More information is required about the application environment and the application code itself.
As background, I have provided performance testing for VAX, Alpha and Itanium systems. What you ask is a project of a few months at least. Feel free to contact me directly if you require more information.