In Firefox the gradient is not as smooth as in Chrome, looks like they are using different scaling algorithms. It's more noticeable with higher sample area settings:
It looks this way on Chrome for Android as well. I thought this was the intended effect.
Yeah, I thought it was a joke. I'm glad the grandparent pointed out that it could be a browser issue.
For me, Firefox renders boxy pixels on OS X and smooth gradient on Windows. I filed a Firefox bug for this difference in scaling: https://bugzil.la/1238304
Yeah, seems like it is bilinear interpolation in Firefox and bicubic in Chrome.