OS X has a very nice looking HiDPI mode where the effective screen resolution is only the half of the monitor resolution, but with very smooth looking fonts. Is something like that also available for Windows 7 or Ubuntu 12.04?
Windows have dpi settings since long time ago. But most programs simply don't respect windows' dpi, so running a program in a different dpi setting in windows XP or earlier often result in severely broken interface with overlarge or supersmall text, and blurry or pixelated graphics items.
Since windows Vista, MS has added another scaling style in which all programs are reported to run on a 96-dpi screen and then be scaled uniformly, except when the app explicitly states that it supports custom dpi, which results in a blurred interface but large enough to be usable. But they still defaults to the old XP style scaling until windows 8.1
In windows 8.1 MS has completely removed XP style scaling options and you can only turn off that for each app individually. Also windows 8.1 provide a new 200% dpi scaling option which you must manually set in windows 7, and the result will almost be like OS X's HiDPI mode. It also supports different dpi setting for each display
Although windows 7's hidpi support is not as good as windows 8/8.1 but still much better than XP and previous versions.