My 15+ years of windows tech support experience gives me the gut reaction that this is a windows issue, either your hardware itself, drivers, or settings.
I have made similar solutions in filemaker 13 on windows that does not suffer the same pixelation that you have. But at the same time, have slight variations when viewing on different machines.
Unfortunately, it's a major downside of windows, the possibility of millions of hardware combinations. Where on mac you only have a few, so it's easier to control quality.