However it is achieved, the situation is AC on an I5 2500k is pretty even across the cores, of course this achieved through software optimisation, hence all the complaining with titles such as Arma and World of Tanks that don't optimise properly for multicore.
What your article seems to be talking about, is the same software can be compared on two systems with different configs and the comparisons are rarely 'apples to apples' comparisons, and on that point I wouldn't argue. Thats not to say though that the performance tab in Task manager is inaccurate, it is most certainly not. It's just that me showing a graph from task manager in the same senario in AC as you for instance wouldn't necessarelly mean too much without detailed system specs to give some perspective.
For instance as a result of this discussion I ran 24 lotus's at Silverstone yesterday while my CPU was at stock, and for brief instances I got the 'High Utilization' message. I have now OC'd to 4.2Ghz and will report back with results.