The problem is that there is no sensor- on these mobos, an external probe is necessary to assess NB temps. I am guessing that the article reports mobo temps- I believe the mobo temp sensor is near the NB, but is definitely not an accurate indicator of NB temps.
There were several reports on SPCR of temps >80C with the Zalman NB-47J passive cooler; the A8N-SLI Premium heatpipe cooler even reaches upwards of 60C, and ASUS specifies that the heatpipe will keep NB temps <70C.