I don't really care about all the different display modes, because I've always noticed a decrease in performance on anything but Standard, especially DirectX + VRam. It doesn't work the way you'd expect it, so don't question why it's slower.
This is changing though, with the new Hardware Acceleration beta being out now, there is Direct3D 8 and Direct3D 9 which both support pixel shaders and run a lot faster then Standard does.
The only thing I've ever used is Vsync. Which only works properly if your refresh rate is synced to the games framerate. It stops tearing when scrolling.