I'm drawing my game on a render-to-texture FBO with multisampling. The multisampling works as expected, except for one thing:
(left is a untextured quad, right is a textured quad--the texture is much larger than the quad, the cross in the center of the texture is 2 line primitives)
As you can see, textures seem to suddenly have better downscaling at 9+ samples. Im trying to figure out why this is, because I'd prefer to have this quality of downscaling all the time (even if I'm at, say, 4 samples). The artefacting in the first two images is pretty ugly. I'm not using any mipmapping here, but I did try that as an alternative to this, and it does look much better. However, mipmapping looks a bit blurry compared to the third image, and is still not preferable in comparison.
This was rendered with an NVIDIA GeForce 980M, and it appeared to have the same behavior on other nvidia cards.