I don't know any utility to change multipliers from Windows, so try jumping into BIOS. I never had any Gigabyte boards either, so I don't know what the BIOS looks like. So, I'll just do what I can do, which you can actually do yourself, find a review of this board and see what the BIOS is like.
Here's One.
Firstly, to access the BIOS, restart your PC. Right at the screen where it checks your CPU speed, amount of memory, HDDs.... press Del button (it's located on the bottom right corner of the keyboard in the numpad area). Press it a couple times just to make sure.
Once you're in the BIOS, navigate down to "MB Intelligent Tweaker(M.I.T.)" and enter.
At the top, you'll see CPU Clock Ratio, change this to 9, or Auto if available. Then press Esc.
Now, if you're not overclocking and like to slow the CPU down when at idle (Speedstep), navigate up to "Advanced BIOS Features" and enter. Find "CPU EIST Function" and set it to Enable. To further cool your CPU, you can enable CPU Enhanced Halt (C1E). Finally I'd recommend to have "CPU Thermal Monitor 2(TM2)" Enabled as well. Then press Esc.
Once you're all done with that, on the main menu, navigate to "Save & Exit Setup", press enter, and say OK to the confirmation.
And eh, that should be it I guess. Try it out and good luck.