I suspect the issue may be down to however your computer, which I'm guessing is running Windows, is rasterising the font. On Mac OS, it renders perfectly, wheth

I suspect the issue may be down to however your computer, which I'm guessing is running Windows, is rasterising the font. On Mac OS, it renders perfectly, whether on a Retina display or a normal monitor. Ditto for Ubuntu. It looks like ClearType is making certain elements of the typeface finer and lighter. You might want to tune your ClearType settings.