One thing that made our 3D carving go way down in speed is better toolpathing via better software.
I don't know anything about the CAM you're using, so take this with a grain of salt. But when we went from using Ventric's Cut 3D, where you just raster everything out, to Ventric's Aspire, where you've got much better control and more options for the 3D toolpaths, well, our toolpath times dropped quite a bit because we could be smarter about the moves the machine made. I'm certain that Artcam or others (and maybe the CAM software you're using) has even more and better options, but I thought I'd throw this out as well.