Tangentially related
The 8 hour graph title indicates 1 minute average. But he graph granularity is 5 minutes. Doesn't that really make it a 5 minute average? Average of five one minute averages. Is that not the same as a five minute average?
Thus the title is a little misleading in that it seems to indicate the granularity of the graph. But looking closer at the time scale reveals the graph to have a 5 minute granularity.
http://forum.pfsense.org/index.php/topic,58158.0.html
Ah that's getting closer to what I'm seeing.