Originally Posted by Al1943

But the difference in the derailleur's actuation ratio offsets the difference in the shifters' cable pull, if both are 10-speed. The derailleur and chain move the same distance and so you are doing the same amount of work either way. On the other hand the there may be a difference in total friction between the two systems and I don't know which has more or less friction. My guess is that the 7900 may have more friction due to a more complicated cable route.