Originally Posted by
nightkhaos
NB: there are only 24bits per pixel, not 32bits, on the final raw output, the 8 bit alpha is processed internally and is used in situations when you have one image superimposed over another. This could change when OLED screens become more popular as you could have a "see-through" screen, thus the 8bit alpha will have to processed with the final output image as well.
I guess you do have a point, even a small display (by today's standards) of 1440x900 would require bandwidth of 226.8 MB/s (that's megabytes, not megibytes, can't be bothered doing binary based division). But you also have to remember that in very rare circumstances will a complete "dump" of the video need to be given over the bus. Even moving windows between screen shouldn't require a complete dump, but you're right, I didn't realise the bus for PCI was only 33MiB/s...