Q:Activity monitor...how do I get it to show all 8 cores in the dock icon?

[BillMac]

IIRC, when I was at the Apple Store messing with the quad-core Mac Pro I could have Activity Monitor show all 4 cores. It showed them in the vertical bar graph in blue. I'd like to do that with mine, just to see what I can throw at it (and it's pretty!!).
I've looked through the preferences, and all I can manage is the old-school looking green dot-matrix graph.

Any ideas?