windows on retina display shows up icons too small

From Using a Retina display - Apple Support

Adjust the Retina display pixel density in Windows

Using the Apple-supplied Windows Support Software, Windows starts up with the maximum dpi (pixels) it supports (144 dpi, or 150% magnification). As a result, items on the display appear small with a lot of space. You can adjust this setting using the Windows Display Control Panel.

It looks like you're limited to whatever control Windows has in place for enlarged fonts and icons.

tt2

I'm not sure there is much you can do to improve things. I think the article essentially says that it is an expected problem. You could turn on the Windows Magnifier which would give you an enlarged view of the area around the cursor, but you might find that equally unsatisfactory.

You can use the Set Custom DPI setting in Windows to go to 200% or even higher (see http://www.tenforums.com/tutorials/5990-dpi-scaling-level-displays-change-window s-10-a.html) but that may not affect every element in every application. You can experiment with the effect of the Use Windows XP style scaling option. I just tried here and Word, for example, scales up all toolbar icons and menus evenly, whereas iTunes draws the same size boxes for icons and other components but uses larger text. i don't have a Mac display, but I take it the option of choosing a different display resolution which is then scaled to fit isn't available.

tt2