@jimp:
Difficult to say without more detail, but on smaller hardware, just watching the dashboard on its own will cause a spike in CPU usage because it takes a fair amount of CPU time to process all of the data required to draw the dashboard.
In other words, the act of measuring can change the results.
Even on my i5 quad-core, viewing the web front-end bumps the CPU from 300mhz to 800mhz-1600mhz due to increased CPU load.