Originally posted by XanderF

(As an aside, I have no way of knowing....for sure....that this is what is happening. It just seems during very intense 3d scenes that my video card just stops for a while - say, 30 seconds or so - and when it starts up again the framerate is much lower. From what I understand, that's a symptom of the card auto-downclocking. During cool periods of the day, it doesn't seem to happen - and, if I run it at 475 instead of 485, it seems okay as well.)
Textbook description of the 5900 cards throttling back the core speeds. I'm curious as to how it determines the scale-back speed, though. I know it doesn't default back to 300mhz (like in 2D mode), as when I clock the core at 500mhz with poor cooling, it will throttle to ~370mhz. Seeing as it clocks from 400mhz to 300mhz default, it could very well just be 75% of the default speed. Perhaps this could be another way around the throttle, by just setting the clock speed 33% above what you want it to be?