Well I wonder if those pieces of hardware purpose goesfurther, a bit like the decompression units free the cpu, I can see those units freeing the GPU /Rops of the "dumbest" operations.
Pretty much I wonder if the gpu could render the render targets and then be completely done with it.
Along with the dme those units would load the different RTs do the scaling and blending and send the result to the display.
I don't know how those units interface with the esram and the main ram, but in the best case scenario (the system is designed so those units do the blending for free "as far as the gpu is concerned they are provided.with enough bandwidth, etc) I could.see.that being a massive win, a lot more relevant to the system rendering capabilities than the move engine.
As for the UI, I would make sense to me if it part of the "system" screen. It would make sense for MSFT to present sort of an API for the UI that include proper polices scaling etc.
Following up from 360's built-in scaler...
For this display plane technology, it is also a convenience feature since, like PS3's split memory pools, someone needs to move or blend the last frame data from whichever pool to its final resting place (Durango's display planes). Its advantage is we don't have to care what exactly the apps/games do (e.g., wireless display, 3D, 4K TV, etc.), everything works uniformly in the display planes.
Resource saving techniques can be done in software also. So I don't necessarily think it's a big saving win comparatively. However because the OS knows the final frame will always be _structured_ in the display planes, they can employ more tricks uniformly to all the apps and game output.
On Orbis, Sony will have to do it via software libraries for each of these modes (3D, wireless display, general purpose OS integration, multi-console rendering, blah).
Don't see how it would be useful for 3d where you'd have 2 basically identical planes. It wouldn't save you anything.
Unless you could somehow have only part of the frame 3d by using planes.
I suspect the display planes will be complemented by a set of library calls to enable more interesting (and flexible) use cases, but that's just my guess.
EDIT:
If my guess is correctly, then people probably can't see the real benefits of these display planes until they see the Durango OS running for real. I think resource saving is secondary (and there are substitutes using software), these display planes should be able to enable new and consistent user experience in the final OS. ^_^