I've got my old laptop up and running w/ Elementary OS Luna (Ubuntu 12.04 LTS), and installed the good old
fglrx-legacy (I have an old Radeon Mobiliy 4xxx). I then installed Steam for the game streaming. But I get constant artifacts appearing all over the place. Underneath them the service seems to be working fine. I tried with and without hardware acceleration, both times it fails to work correctly.
As for the artifacts themselves, it's the typical bits of the screen being deformed, put in other parts of the screen, and sometimes working for up to a second.