I collect them, and the 9800 GTX+ is gonna be my new physX card. My main reason for getting the hd 4830 was so I can get some clear results on the whole crossfireX downclocking thing.
Really weird shizz goin on with that btw. If the card is the same (as in same GPU clock BIOS) they do effectively downclock, but with different BIOSes or different cards, they perform inbetween.
I am definitely gonna try to figure out what the exact cause of this is.