The graphics card is not the best I've seen but it can support big resolutions and work very well in terms of performance... but there's a catch.
You see, I have the same graphics card on my laptop as well. Under Linux I'm experiencing the same problems and I see no workaround for it since we simply don't have an adequate driver. On Windows, it runs PERFECTLY. So, who's with me to go to Intel's door armed with some forks and axes tomorrow, ey?

Seriously, under Linux, if I want to run the game I have to decrease resolution, colour depth, etc to work, just as you all stated. But the best workaround for this is... (I CAN'T BELIEVE I'M SAYING THIS

) is to run Windows. For PlaneShift, I made a sacrifice... and it was worth it from my point of view.
Now for a more permanent sollution and which doesn't restrict your choice of OS anymore is to buy an actual graphics card that can support Planeshift without problems - NVidia and ATI cards come to mind.