While on my mother's powerbook (1.33 ghz g4, 256 ram, 15"), i noticed all these weird things appearing, basically a polygon of texture appearing at certain angles, I would see several of these at a time. I notice it sometimes on my iBook (900 mhz g3, 12", 384 ram (at time of noticing)), it is quite annoying because well, it looks odd.
The texture that usually appears is that of rock.

Both computers are on 10.3.2

Also, in s1 when inside the center of the station, some polys are missing.

If you could get a screenshot of the problems, that would help.

They should be sitting in your e-mail box.