However, there are data that by definition are excluded from being cached, the best example is the video memory that is defined as uncacheable. What that means is that the data that are finally coming up on the monitor are excluded from the cache and consequently from write allocation. What that also means is that each calculation resulting in new data, e.g. in terms of 3D processing, results in a stalled processing operation because the data need to be written to the memory. In this case the memory is the video memory or frame buffer. Of course, the higher the amount of data resulting from a 3D operation as e.g. filtering or bump mapping, the larger will the chunk of data be that needs to be stored.
Higher resolutions create, or depend on, a higher amount of data that are being processed.
Vice versa, lower resolutions can be achieved with less data and, therefore, the amount of data that are written is smaller. Still, no matter, whether it is one bit or 10 bits, the data need to be written, thus causing a stalling of the actual video processing. Therefore, there should be only little difference between the video performance at low resolutions or at high resolutions. The Intel PentiumII has taught us that this is not necessarily true. This way, the smaller the textures, the smaller are the amounts of uncached writes that can be combined to a single burst sequence or, to look at it from a different angle, more writes can be combined until a write needs to be physically executed which causes stalling of the video processing per se.