I ran a few tests to document the differences between the fair queuing and FIFO queuing in Cisco IOS as well as the impact of queuing mechanism on the software/hardware queue used. The results are stored on CT3 wiki.
Ivan Pepelnjak, CCIE#1354, is the chief technology advisor for NIL Data Communications. He has been designing and implementing large-scale data communications networks as well as teaching and writing books about advanced technologies since 1990. See his full profile, contact him or follow @ioshints on Twitter.