The "5.5 GB" peanut gallery comments all conveniently ignore one obvious fact.

When Nvidia cut down the 970, they reduced the effective memory bandwidth, but, for obvious marketing reasons, thdy did NOT reduce the total amount of installed VRAM. The 980 architecture has exactly as many ROPs as it needs to run 4GB at the full advertised bandwidth. The 970 has less, but still has to manage 4GB somehow. Hence the segmenting workaround.

The 980 Ti also undoubtedly will have a reduced number of ROPs and less L2 cache. It may even have more controllers disabled than just the ones involved in the two SMM blocks that are turned off. BUT, it also has 1/2 the VRAM installed, compared with the full house Titan X.

So with this card, Nvidia can afford to lob off a bunch of ROPs and still have enough left to run 6GB at the same effective bandwidth that the Titan X does with twice as much.

Even if there is some nominal bandwidth reduction, it's unlikely that there will be a similar breakpoint or segmentation in the memory on this card, becuase it will be able to handle the full 6GB installed VRAM capacity without resorting to that.

The same would apply even to an upscaled 980 Ti "Metal" or "Black" edition, if it winds up with 8GB installed. If they ever come out with a cut-down GM200 using a full 12GB, then that may merit a closer inspection to see if they needed to resort to segmenting or some similar kludge to make it work.

Even then, they can always just do what they did with the 960 and install more VRAM, but let it run at lower speed. The 960 runs the same in both 2GB and 4GB forms, with no segmenting. It's just a whole lot slower than the 980 because it is exactly half the chip that the 980 is.