It has always been my understanding that Amiga HD floppy drives operated at 1/2 the speed of 880kb drives to write the 1.76mb format to a HD floppy disk. I did not think this had anything to do with buffers slowing down the transfer of data. Someone correct me if I am wrong.
That's correct, it did access at half speed, which is why using high-density disks in the Amiga was so slow. As I recall, it was because Paula (which handles the floppy disk IO) is incapable of dealing with the data at full speed.
