OK glad clearing the cache fixed the problem with the excessive drawing popup.
Your machine should be more than capable of running Voxel layers, so I'm at a loss at what could be wrong there.
One thing to check is that you're using DirectX in display options - early releases that supported Voxel layerse didn't work with OpenGL - the Scene Layers team has fixed that in 2.7. Additionally the upcoming 2.8 release has some fixes for layout display of Voxel layers, and some were back-ported to 2.7.2, so make sure you're on the latest release to pick up these changes.