And you haven’t setup an NVidia Profile for Rhino? If you’ve turned off VerticalSync permanently and are still seeing 60fps, then something else is turning it back on. When I do the same thing here with V7 WIP, everything works as expected… and if I set NVidia to “Use the 3D application settings”, then Rhino’s “-TestMaxSpeed VerticalSync=Disabled” also works as expected.
If you’re seeing 60fps with an empty scene in a wireframe view, then I’m pretty sure you’re still experiencing the vertical retrace delay. I’m also not understanding how it’s possible that your V6 Rendered mode is faster than its Shaded mode…that makes zero sense…unless you’re not working with the default settings for either of those modes.