Re: Nvidia 6200 and ATI RS480/482 chipset incompatibilities
I'm impressed by the detail of your testing processes, and the wide variety of OS' you've used to test the 6200. I too notice improved stability when lowering clock speeds, however, I believe this is a fairly generic fix. Lowering clock speeds means the card is put under less stress, and thus, the bug in the driver that seems to arise due to high load is less likely to occur. I do agree that underclocking a card typically improves stability, though.
Regardless of if stability improves with better cooling or not, the main point of your tests is that they are a workaround. We shouldn't need to apply them though, since a bug that causes the host system to lock up should be fixed. Hopefully the next driver release will address this issue, but it'd be interesting to see what Nvidia's development team are doing as a workaround.