I recently bought Rhino 6, and found that models that my computer can handle in Rhino 5 with relative ease are incredibly slow in 6. While the files are large, in Rhino 5 they caused severe delays only when Make2D or large transformations like Shear were used. Now I seem to have to wait much longer for simple things such as scaling the model to fit the units, or even selecting parts of the model. I can see this issue has be raised in earlier posts, but haven’t found a solution, or even an explanation.
A couple things come to mind.
The OpenGL system requirements were much lower for V5. V6 raised those standards significantly. If you’re running an older display adapter or perhaps one with old drivers, that could be a significant part of the problem.
As far as Make2D goes, for V6, the tool was completely rewritten and in V6, is multi-threaded. That would explain why it is faster in V6.
Start by checking for updates for your display adapter drivers. If you’re running a hybrid system be sure to update both the embedded and secondary display adapter drivers with the most currently available.