What kind of cooler do you have on the cpu? If its the stock cooler then don't mess around with overclocking till you get an aftermarket cooler.
Well i'm currently running the stock but if i do overclock going to be buying a new one. Was just going to see whether my computer can handle the OC first.
I have that MB with the i5 4670 CPU and it handles OC rather nicely!
To answer your question, yes, you can increase the Turbo multi in the BIOS.