I'm not sure what's up, but the 2D rendering has a lot of horizontal white lines - gaps in the fill - even on simple things like the Red Ellipse demo in Chris Anderson's XamlPad. The Windows Forms demo is really bad - the Windows Forms controls don't even display initially until you click in their corners; once it's running, you can't switch to a different demo, nothing happens.

As for Chris Sells' Solitaire - I know it's not optimised, but ten seconds to turn over a card?? The gaps are green, the same as the background, and there are a lot more of them.

Daniel Lehenbauer's Boing demo works fine, however.

System spec: 2.8GHz P4, 512MB RAM, nVidia GeForce Ti 4800 SE gfx card with 64MB video RAM. Running Windows XP SP2 as a limited user, using nVidia's version 66.93 drivers.