For another benchmark of Pierre's "improvement," a simple test of
SortedCollection>>select: such as,

  | co ra |
  co := SortedCollection new.
  ra := Random new.
  5000 timesRepeat: [co addLast: ra next].
  co reSort.
  Transcript cr; show: 'Select: ',  
      (Time millisecondsToRun: 
          [co select: [ :i | i odd]]) printString, ' msec'; cr.
 

took 15 sec on a 450 MHz Pentium before changing the add: to addLast: in
OrderedCollection>>select: and 50 msec afterwards!!!

Let's see, 15000 / 50 = 30000%  "improvement."

-- 
stp

Stephen Travis Pope  --  http://www.create.ucsb.edu/~stp