For comparison purposes, rack #1/slot #8 of the OSADL QA Farm hosts an Intel Atom CPU Z530 @1600 MHz board that runs a stock Fedora 12 kernel and undergoes the same real-time tests as the RT systems mentioned in the article. Let the images speak for themselves:
Most recent single latency plot -> https://www.osadl.org/?id=869
Repeated latency plots -> https://www.osadl.org/fileadmin/media/r1s8-60.jpeg