this came out some time ago but...
by any standards overclocking with a permanent phase change system is still overclocking.
whether that's impressive or not is another matter.
even overclocking with LN2 is still overclocking. It is not useable overclocking, but it is still overclocking.
again, whether something like that is impressive or not, is a matter of your own opinion.
Of course I'd be much more impressed by someone getting 5Ghz using more long term cooling, but I can still appreciate that some skill is involved in getting a real screeny at 5Ghz. (not to mention a fat wallet)
But about what an AMD would need to be equivalent of a 5Ghz P4... probably a 3.1Ghz FX.