> If I am not wrong also Radeon 800/850 belongs to R400 family.
> They have never been in AGP format?

For AGP there're X800 cards with R430 GPU, which is a PCIe chip, that's connected to a RIALTO bridge chip in order to make it accessible by AGP. And then there're X800 cards with R420 GPU and X850 cards with R481 GPU, which both are real AGP chips in themselves..