There is no definitive correlation between CPU utilization and RAM when looking at diverse science applications. The top usage combination of CPU and RAM is a computational biology application focusing on nucleic acid folding. The computer science application requiring CPU hours is NAMD, a molecular modelling package. The Mecheng application requiring RAM is Ansys FLUENT.
We've deliberately removed the axes data from the graph as the values were changed by several orders of magnitude to display the graphs clearly. While this is not of much immediate use it supports our current plan of splitting our cluster hardware in two, one cluster providing powerful CPUs, the other providing large amounts of (very expensive) RAM.