Tech Report: CrossFire DUAL SLAVE !

I don't understand what the content of your post, point 1) aside, has to do in any way with the switching card. You seem to be saying that SLI is an additional cost because nVidia have decided to make it one. Yes, ok. What's that relevant to?

As to point 1), again I don't see how it's relevant to what you seemed to be saying earlier. Autoconfig has been commonplace in those things because a) they're mature technologies and b) to the best of my knowledge most don't involve changing the physical connections between components. The only way to do this on the actual southbridge (on A64s) would be to have a full set of 16x traces to the primary slot and a full set of 8x traces to the secondary slot, which is probably a pain in the ass from a board design POV, and requires support from the southbridge, which presumably isn't present on the nForce 4 SB. Until this is done, there has to be some kind of discrete switching solution because there aren't enough PCIe interface pins on the SB to do it any other way. Yes, autoconfig is preferable, but as shown it has to be discrete and the chips are currently reasonably expensive. Yes, economies of scale will push the cost down, but the key word there is "scale", which isn't currently present, and certainly wasn't on release mobos. The fact that SLI boards are in the pipe with auto-switching may mark a turning point, but it's not here yet.

In the meantime, the switching card itself is just the cheapest way of rerouting eight PCIe lanes from one slot to the other, and on my understanding that's all it does - changes the way traces on the board are connected up. How is that a "dongle" on your original definition, or in any way proprietory? Or are you suggesting that nVidia have patented this implementation and are licensing it out?

 

And I thought I already asked you whether you think Crossfire certification comes for free... I don't.

(1) I agree that autoconfig has become commonplace in several fields. But we're talking about a technology that is both new and bound to disappear again as soon as chipsets with 32+ PCIe lanes are affordable. Because then we won't need any switching capabilities any more.

(2) I don't know what you're trying to say with that. There is no special "dual PCIe x16 spec". Multiple x1, x4, x8 or x16 slots in various combinations are all part of the original PCIe spec developed by the PCI SIG.

 

It would not make sense from a marketing standpoint for ATi to charge a large fee for Crossfire the way nV applied their 'SLi-Tax', since ATi already has an uphill battle against the acceptance of the incumbent SLi.

 

This have any impact on the convo upstream? [from the X800 XT Mobility pages at ati.com]

 

Are you presenting this as a fact, or as your interpretation? I was was under the unambiguos impression (delivered unto me by an ATI rep, and not the usual suspect in case you are wondering) that the compositing chip not only blends the output of the two cards in super AA mode, but that it adds its own 2x super sampling AA to the mix. He was clear that this all took place on the compositing chip. he may not be right, but he was very clear on the matter.

 

That is a Raja'ism and CrossFire was his baby...
(The 2x SuperSampling is not a result of the compositor, its a result of slightly different pixel centers on each of the graphics boards)