FPS drop down to 3 or 4 for no apparent reason

I've noticed this happening recently, everything will be running fine, I'll have 20fps or more, and I'll zoom out a bit or move my camera, and my fps drops to almost 0, and stays that way until I go into full screen mode and back to window mode.

I took a screen shot so maybe someone can tell me what is going on, I'm not sure how to read the little colored bars, but my fps drops way down whenever there is a full gray bar across the top like in this picture.

I have all of the advanced settings turned off, and everything set pretty low for high fps. It seems to me like it's something to do with the graphics engine, since it completely fixes it when it change the resolution and redraws everything.

After looking at the little bars, the light gray is RenderGeom, which appears to be hanging or something. The very top bar is completely gray all the way across with every frame, until I go fullscreen, which fixes it. Is this a bug?

Here is another screen shot of the RenderGeom problem, this time in the smaller view.

I read in another post that dual processors make SL act funky. The P4 processor has hyper-threading, which makes it appear to have 2 processors, so I am going to set the affinity to one of the processors and see if that helps any. I'll find out as soon as SL comes back up.

I've found ObjectUpdate or UpdateParticles (can't tell since both look the same shade of blue to me) to cause the most lag.

RenderGeom has also been a problem for me, altho it has gotten better over the last few updates. Anecdotally, at least—the same troublespots haven't lagged me to death... I'll keep watching... wonder if we're experiencing the same thing here, Nardenz.