Thanks JAISP, but we don't have a shared environment, we have multiple Sun machines of our own. Supposedly lots of power, and tons of ram, configured to run the forums in an optimal environment.
I have a feeling when there are 600-700 users on the forums at one time it's causing problems. I realize they aren't all concurrent, but apparently enough are. Or it's that combined with extensive searches.
Of course, I'm just guessing.
I'm hoping between Allen and Mathx they can figure out the cause and solution, as it's beyond my feeble tech knowledge.