Sim FPS - what is it? and what affects it?

I'm curious as to what the Sim FPS is really trying to indicate. I have been in very crowded sims with both high and low FPS counts, and I've been in very empty sims with both high and low counts. Does anyone know what really has the biggest effect on this number? Does this number directly relate to the performance of the sim? If anyone can shed any light on what this mysterious number is and what it is trying to tell us I would really appreciate the information.

Thanks.

SimFPS is a very "kludgy" thing, honestly. It's supposed to represent something like the total amount of "free cycles" or somesuch that the server can still spare to things. Or something like that.

Take a look at the Run Tasks, Run Agnts, and other things down on that Alt-1 thing too. The higher those numbers are, the lower SimFPS gets. Those numbers are actually a better measure of what's bogging down the server. They represent how much time the server is spending on various types of tasks.

BTW, a sim dropping from 1000 SimFPS to 500 SimFPS is EXACTLY EQUAL to a sim dropping from 4000 to 2000. It's a math thing. Percentage of drop is much more important than actual values.