Sorry for starting a new thread about this, as I think this has been stated somewhere already, but after googling and searching the forum, I couldn't find it.
It's well known that in DX9 mode, the engine treats graphics as if they're in set sizes, based on the power of 2, like 32x32, 64x64, 128x128. So in terms of how much RAM/VRAM is actually consumed, a 400x400 graphic becomes 512x512, for example, while a 513x1025 graphic would become 1024x2048.
I think I read once that this no longer applies in DX11 mode (ie. a 174x298 graphic will consume 174x298 worth of resources only). Is that the case? And if so, does it apply across the board, or just partially (eg. a 174x298 graphic consumes fewer resources in runtime than 256x512, but the same amount in edit-time....or perhaps it consumes less RAM, but still makes the GPU work harder to 'draw' more empty pixels)?