also if you notice that bars accross the screen dont seem to be in sync...
...you may want to try enable vsync.
something to note abbout chuggy graphics, if your using a radeon, dont use display lists, for some reason there is a memory leek on some cards(i used to think it was a problem with garbage collection but i was wrong), vbo's work just fine though.
[...]128 was just an example value. You can see the odd behavior at any limiting value. Just create a small scene, where a shape is constantly rotated over the screen. If you use a sleep() with any value in the main loop to prevent the CPU from being used at 100% you will notice the shape juddering. That's what I am talking about.[...]
That's tearing. You get that if vsync is disabled.