I am seeing this xv video stuttering with 180.44 drivers. It is particularly well visible with mplayer -nosound -benchmark -vo xv. Using -vo x11 or -vo gl avoids the stuttering.
The stuttering itself displays as two consecutive frames alternating for a fraction of a second or more before the playback continues. In MPlayer benchmark this also shows up as low performance (compared to x11 and gl outputs) because it spends half the time stuttering.