WPF does support ClearType, but there are some changes from the version
used by GDI+. In your screen shots, it looks like the clear type is not
being supported at all. The WPF text team has some tips for improving clear
type performance with wpf:
A couple of points that may be relevant:
level, WPF will automatically render using grayscale anti-aliasing. Due to
our pixel independent architecture we cannot render aliased text even if
â€˜font smoothingâ€™ is turned off completely."