Illustrator adding weird lines on shapes

[Joel24014355mpbg]

In this screenshot I have two squares the exact same size perfectly ontop of eachother yet there is a weird outline of the bottom shape even though both have no outline. While I'm just using this as a way to show the issue these outlines seem to show constantly. The lines do not export, but make doing work difficult. How can I fix this?

[Joel24014355mpbg]

For reference there is a blue square with a white square on top. Both are the exact same size on the exact same spot. Outlines change depending on zoom.

[Ton Frederiks]

That is caused by anti-aliasing.

If you turn off "Anti-aliased Artwork" in the Preferences and switch to View > View using CPU it will go away.

But the preview becomes slower...

[Joel24014355mpbg]

Switched to CPU still there. 

[Bobby Henderson]

I wonder if the size of the squares and their position on the artboard could have something to do with the problem. I'm thinking the raster effects resolution setting could be a factor. If the squares aren't lining up perfectly with that imaginary grid it could be a reason why those glitches are appearing on screen. 

[Ton Frederiks]

Did you also turn off "Anti-aliased Artwork" in the Preferences?

[Joel24014355mpbg]

Forgot about that. If I do it it does make the lines go away, but frankly the quality drop may not be worth it.

[Ton Frederiks]

That is what I said, it will be slower when GPU Preview is turned off.

Anti-aliasing is what is causing this.