Completely depends on the rad and the fans - and how good the chip is itself.
You can easily get to 4.5/4.6ghz on most air coolers on Ivybridge - just higher than that requires a lot more volts - which isnt really worth it on temps and life of the chip.
You arent gunna see barely any performance difference between 4.5 and 4.7ghz anyway, so I'd personally prefer to just go for 4.5ghz and run fans at very low RPMs so it's quiet