Removing both heatsink(s) (CPU/ChipSet/VGA), and applying artic silver should cure that. I added a piece of aluminum from a floppy disc, to place in between the VGA and the heatsink, applying artic silver between both sides. I leave mine on 24/7, and temps never get out of hand, and that's a good thing when gaming. NO MORE CHOPPY CHOPPY (after 10 minutes of game play) LOL! Now it's time to see how far I can set the FSB.
Underneath the palm rest where the hard drive resides, is a cooling plate for the hard drive. I added a couple of pads between that, and now I have a luke warm palm rest, not that it was ever really hot to begin with.
Just out of pure bordem, I took a keyboard from a XPS and put it on my D600. Wow!
Didn't expect it to be nice and firm, what a difference!
Just thought I would share that, later all!
None of the advice above will let you play HALO at max settings, but it will make things much cooler. Even when I do get another notebook, I plan to keep the D600 as long as I can, good notebook!