Eh in my opinion overclocking to the absolute max isn't always needed, as that last few frames always costs a lot more in power and heat output.
Just do the standard 10-20% over and be done with it.. oh wait thats not the Hard way, but thats fine for most of usLike with SB, peoples obsession with 5Ghz when 4.6Ghz suits me just fine...
What about way underclocked cards, released 100-200Mhz under what they were deigned to run at stock like their big brothers? adding 10-20% doesnt even get you to same stock spec. Like for eaxmple buying a 448, which is fed 0.2 less volts and 100mhz less than same chiped 580? Or 7950/7850s? List goes on but you get the idea 10-20% anit anything unless you're already buying top cards. 7950 has 40-50% left in it. 7970 sure doesnt.