Yesterday I changed the OS of my workstation from Arch Linux to Windows 10. I had KiCAD version 4.0.7 under Arch, and the same version under Windows. Hardware is exactly the same (except for the disk drive). GPU is integrated with the CPU (Intel i5-6500 / HD Graphics 530).
One thing I noticed: the 3D view under Linux was much "smoother". By that I mean the render quality under Linux was almost spooky in its realism. Under Windows, it's as though it's being rendered for a lower-resolution display: the gradients are more evident, straight lines look jagged. Even the fonts on the silkscreen are (were) more readable under Linux. To me, it reminds me of whether or not anti-aliasing is enabled for fonts.
A couple screenshots:
Image 2 - Linux
Image 2 - Windows
It's not a dramatic difference, but it's there. Look at the white silkscreen component outlines, or white silkscreen text. It's particularly noticeable on the pin headers on Image 2.
I played with the 3D viewer options in KiCAD, but was unable to affect the smoothness.
I suspect this is a system-level issue, but I don't know where to look to experiment with different settings.