***UPDATE*** After playing a bit with the settings I can confirm the problem is limited to fullscreen mode. If I set the game to borderless window I can definitely see the automatic dynamic resolution setting kicking in; it's quite visually noticeable and my frames remain locked at 60 (Also using in-game FPS counter and Rivaturner). I tried several combinations with or without VSYNC, anisotropic filtering, and anti-aliasing methods. The only setting that disables automatic dynamic resolution is fullscreen. I don't know if this is the expected behavior.