RSX aren't capable of HDR+FSAA?

[Mintmaster]

But RSX isn't a 7600GT it can magic up more bandwidth due to the split memory pools if bandwidth was the limit... ROP rate is a much more interesting figure IMO
Colour compression does work in non-AA mode BTW its just not very effective (for obvious reasons).

I don't see it happening. Trying to render into both XDR and GDDR simultaneously is a mess. (Does RSX even have this ability? Simultaneously?) The write buffers are going to be engineered with the GDDR3 latency in mind, because that's how 99% of people are going to use it. Absorbing the latency for XDR and FlexIO would require wasting transistors for something no-one will use. I don't doubt all the vertex buffers will sit in the XDR, and maybe we'll see some texturing from XDR in certain circumstances, but anything beyond that is dreaming.

What's more is that the 7600GT is bandwidth limited (during color+Z fill) with half the ROPs of RSX. Even if RSX could magically double it's bandwidth in the way you're talking about, at best it would have the same ROP/bandwidth ratio of the 7600GT. It won't achieve 16 pix/clk for RGBA or 8 pix/clk for FP16. ROPs are in abundance.

BTW, one thing still bugs me from above. Why are you guys clearing the color buffer?