Like their predecessors, they come with Intel HD Graphics (integrated graphics), and there have been reports of freezing and lines on the screen (mostly freezing) when running many Linux distributions.
Since I just built a new system with a Core i3 3220 processor, one of the low-end models, I decided to see what the heck is going on between the Linux and Ivy Bridge. Note that the Core i3 has an Intel 2500 integrated graphics, but almost all the reports I have read have been with Core i5 and i7 processors with Intel 4000 integrated graphics.