I recently installed my intel i5 3570k on a biostar tz77xe4. I tried doing some mild overclocking however, I noticed that trying to change the multiplier is next to impossible. It stays at the stock x34 multiplier. I'm using CPU-Z 1.60.1 to verify
A lot of us are overclocking by changing the multiplier for Turbo mode. This should work for your board to. I used the Intel® Core™ i5-3570K and the Intel Desktop DZ77GA-70K and overclocked it to 4.6GHz stable at 1.2v.. I know some other overclock the main multiplier but from what I have seen not all boards support it.