What Happens when I change processor frequency of my android phone

I have Xolo x900 phone. I have settings to set the processor frequency. It is defaulted to 600mhz, yet my phone has a maximum of 1.6Ghz. Can I change to 1.6 GHz? What would be the side effects of increasing the frequency? Will it overheat, drain my battery? Also, would like to know what would be the advantages on increased frequency.