My Intel HD Graphics 2500 says is running at 350 MHZ! Can it be?

Hi there! I´m using th i3 3220 IGP. In its data sheet it says that its base frecuency is 650 Mhz, i performed an OC to 1200 Mhz, and when its idle, the SAndra 2012, PC Wizard, Aida 64, all of them says that its working at 350 Mhz. I suppose it should be at 650 Mhz, i´m just curious, ´cause when i need te full speed it goes to 1200 Mhz. Is that OK? Thanks!