trying to overclock my cpu its a 4670k cant get over 3.8

[n7 daz]

trying to overclock my cpu its a 4670k on a z87xud3h mobo ive set it to 4.2 following a guide but when i boot up the pc its only at 3.8 tried it 10 time when i go back to the bios all the settings are still set at 4.2 but on the side its on 3.8 with a 38 multiplier so i click the run now thing and it goes up to 4.2 so i save and boot but 3.8 when booted what am i doing wrong please help

 

[DonkeyOatie]

That looks like the Turbo-boost speed, are you sure you are reading the right thing or are changing the right value?