listed monitor refresh seems too high

well, I’m using opensuse 11.0 and I have a Samsung Syncmaster 226CW along with an ATI HD 4870. In Gnome. Now, the video looks fine BUT. What I have it set to now is VesaFrameBuffer I think was the default since I don’t have the video card driver popped in there, and there was an entry in the monitor list for a 226BW which should be fine. I go in and look at the horiz and vert freq ranges and they are exactly the same as what is in the monitor handbook. HOWEVER. When I go into the “change resolution” area, it tells me that it is running the monitor at a refresh rate of 77hz. So, the question is, is it running the monitor in digital or analog mode, and is that number correct or not? Because if it is running it in digital mode and that # is correct, then I am WAY overdriving my monitor. Or is it running in analog mode and I am fine? OR, is it running it in digital mode, but the # is wrong? Because when I click on the menu for the monitor itself, it says that it is running in digital mode at 60hz. Soooo, what information am I to believe?