badass
In the handful of titles they actually worked in. For nothing more than e-peen bragging power as through the FPS was high, it turned out that they weren't rendering the frames equally apart. Of course, all of that is after endlessly faffing trying to get it to work.
However this does look like an exciting angle. Memory in the bridge. Clever use of silicon. More excitingly, should this be released, it will likely become the regular option rather than xfire/SLI and so not suffer from the problems with being a niche technology. Such as endless faffing to get it to work.
Well, that's rather the point yes? With an all-sorted by-default solution, the driver issues, game support issues, developer/engine specificity problems should disappear, and with modern lithography some of the power draw might* go too. Not to mention the extras like you mentioned, intelligent cache and hardware optimization for utilizing more chips. What was possible on ye olde multi GPU was very impressive despite being so patchy and unreliable!
What worries me is that you won't get the control of buying seperate cards or setting them up how you see fit, just like old single-board dual-gpu cards they could end up expensive, rare, hard to get, in a market where even small single gpu parts have been recently MIA.
*Probably not though lol