Viewport Performance Question imac 5k


Recently i picked up a Late 2015 imac 27 inch 5k Machine.


  • 4.0GHz quad-core Intel Core i7, Turbo Boost up to 4.2GHz
  • 16GB 1867MHz DDR3 SDRAM
  • AMD Radeon R9 M390 with 2GB video memory

I installed blender and i am seeing some very weird view port performance issues.

When grabbing /moving/scaling /rotating objects as simple as a cube i am getting very laggy movements.

Does anyone know how i can solve this issue?

Any help is appreciated!

Thank you

Hi, even iMacs using laptop parts and performance is only 50% of a desktop system a M390 should run such simple files smooth.
Check different Selection and Window Draw Methode in User Preferences > System
Check if you have the latest driver for your card.

Cheers, mib
EDIT: Blender 2.78c is ready next days, check this too.

Ensure you do not have snapping enabled (magnet icon on 3d view header)


Thank you guys for the suggestions!

So to answer a few questions:

I have tried the different drawing methods but while one of them makes grabbing scaling and rotating work smoothly, it also makes the zooming panning and rotating the viewport slow.
I have yet to find a good combination of making both smooth.
Hopefully the new version helps the issue.

Richard Marklew:
I have Made sure that the snapping is not on.

Thanks again for the suggestions !