1GB for kinect? Why would you need all that space? And i'm talking about 1GB for a full blown OS, with desktop, drivers and what not... You don't need all that in a console.
Just to be clear, I don't think 3GB of dedicated ram is impossible, i just want to see on what they would use it. Fast switching apps + media streaming capabilities does not justify all that memory because even windows 7 running applications with no optimizations of memory usage when in background can do all those tasks and more with less than 2GB of ram.
That's still the wrong way to look at it. Another way to look at it is why would you need more than 5 GB of memory for games? Especially if you assume the competition is only going to have 4 GB of memory available for games. Add to that, that unlike the competition, you don't have a large stable of first party developers and hence will rely more on cross platform games and use key exclusives combined with living room services to differentiate yourself.
MS is never going to be able to compete on the first party developer exlusives front. At least not without an absolutely huge monetary investment and the associated risk. So more than 5 GB for games would be a waste. MS can however compete on the living room services/media portal front.
3 GB for "everything else" gives them a lot of breathing room to experiement as the generation goes on. Even if we assume they only "really" use 1.5 GB of memory at launch, you still presumably had 5-6 years to figure out what to do with the rest.
Or look at it another way. Look at the evolution of the X360. While the OS was always contrained to a set amound of memory, the storage requirements for the OS increased as the generation moved on. Services were also added, which means that overtime things had to be pared down and/or swapped in and out of memory (leading to pauses as the apps are loaded) to fit the additional services.
With the next Xbox they are unlikely to run into a situation where they won't have enough memory to do what they want to do, unlike the situation with the X360.
And, of course, that ignores the fact that in the meantime they can make that memory available to the user to have a more polished and a relatively unrestricted (number of apps open at same time for example) user experience.
Now, if you consider that use case. That also opens up another potentially large revenue stream for MS. An application store for non-gaming apps. 512 would unlikely be enough for the OS, drivers (kinect runtimes and databases), included apps, and user bought and installed apps. 1 GB would likely be too little. 2 GB might be enough. But since games aren't going to ever need more than 5 GB as long as the competition only has 4 GB, then might as well make sure you have enough and reserve 3 GB.
In all, there's a LOT of reasons to limit games to 5 GB and a LOT of reasons to have a lot of memory available for non-gaming tasks.
At least some of the memory copy woes brought up might be changing in the future once proper shared address space capabilities make it to APUs. This might permanently disadvantage discrete products, however.
I'm starting to wonder if maybe Microsoft is going to try for a tiled GPU. The SRAM and the engines that manage it could make this easier, and the GPU front end could guide the spill and fill of tiles into the scratchpad. The front end already tiles the screen to help allocate work to SIMDs and ROPs, so extra control signals and output data can be used to set up and fill bins per tile.
Given the comparative brute force of the GPU and the size of the scratchpad, the output and at least some associated buffer data could be rather coarsely subdivided.
Heh, that just reminded me of Microsoft's Talisman initiative back in the 90's when they were trying to decide the direction that Direct3D would take. At the time Micrsoft was wanting tiled 3D rendering to be the predominant rendering method due to how expensive fast memory was. The subsequent crash in memory prices torpedoed that, however, and hence we ended up with the more traditional 3D rendering we have today rather than tiled rendering.
It'd certainly be interesting if MS is again going back to tiled rendering in the face of expensive memory.
Regards,
SB
