PCPER.com: 5 GHZ+ Phenom II Overclock on Dry Ice, 6Ghz on LN2

[informal]

Is that a guestimation, and what is ambient temp.?

That's a range of Vcore needed for that clock.The temp. is not ambient,it's core temp on air at those volts and clocks while running Crysis.Ambient temp should be around 23C,they were at AMD's HQ which is air conditioned i presume.