They're not just going to render everything 1:1 as if it were a 30"-class screen. This is going to work like the 'new' iPad screen and render text at high res

They're not just going to render everything 1:1 as if it were a 30"-class screen. This is going to work like the 'new' iPad screen and render text at high res and images at whatever dimensions are natural for the layout (uses 50% scale up be default, and then will add extra resolution if the source image is bigger than the declared or computed css dimensions)