How does 75 hz and v-sync affect video playback?

[Xcelerate]

Hey all, I just got the 2209wa, and I have a couple questions. I set it to 75hz as recommended for optimum smoothness, however, I edit a lot of video, so I am wondering how this works. Digital video runs at exactly 30*1000/1001 frames per second (~29.97), which when interlaced displays each field at ~59.94 hz. Well, if I have the display set to 75 hz, it's going to be skipping frames somewhere isn't it? In fact, even at 60 hz, it would have to skip frames occasionally since 59.94 and 60 aren't quite in sync, unless of course the playback program just plays the media at 60 hz (which I don't even know how to find out). So any suggestions?

And my other question is simply: should I set v-sync to "Force On" in the nVidia control panel? I would hate to have frames tearing as they are displayed...

Thanks for the help!