Viewport performance on computer with NVIDIA card is quite slow. One way to increase speed is disable the double sided shading.
For every object, uncheck the box :
Really huge improvement.
A little bit cumbersome if you have lots of objects to do at once.
So, keep in mind to uncheck it immediately every time you create a new object.
I’ve found a script to do this for every objects in the scene. Just switch to text editor and paste in these codes:
for ob in bpy.data.objects:
if ob.type == 'MESH' :
ob.data.show_double_sided = 0
and press runscript. (there should be a tab indent on 3rd line, and 2 tabs on 4th line – or you’ll get error when running the script)