This chart shows the estimate of CPU time that the server estimates will be taken up performing tasks. The number is expressed as a fraction. Divide this number by the number of processors you have. If the number is greater than 1, you need more processors.
The lines show the run queue averaged over 1, 5, and 15 minutes. If only the 1 minute line exceeds 1 then that is merely an indication of a spike in activity. If the 15 minute lines exceeds 1, you need more processors.