I5 3570k overclocking stuck at 4.5Ghz

[Corbin2618]

First time actually overclocking without out the OC Genie and I got the chip up to 4.5ghz at 1.32V. Prime95 gets it up to low 70s after an hour. One problem though, when I try to go to higher to 4.6 or 4.7Ghz, CPUID shows that the multiplier has changed, but still shows me a clock of 4.5Ghz. Am i doing something wrong? Does my chip or board have a cap?

Specs are here
Cpu- i5 3570k
Cooler- Noctua NH-D14
Mobo- MSI z77a-g43

 

[Tradesman1]

May have hit the wall, have seen a number of 3570Ks that seem to top out at 4.4/4.5

 

[Corbin2618]

May have hit the wall, have seen a number of 3570Ks that seem to top out at 4.4/4.5

Ah. oh well.