The instant response from my subconscious (the only part working right
now, headcold has turned off all higher functions) is that you might
simply be making use of more _space_ now that you have bigger headers.
It's a tenuous suggestion but ought to be easy to check. Bigger headers
implies fewer objects in the same amount of memory, implies more
frequent incremental gc. Sanity checking arithmetic left to the
reader...

 tim
-- 
Tim Rowledge, tim at sumeru.stanford.edu, http://sumeru.stanford.edu/tim
Strange OpCodes: SNARF: System Normalize And Reset Flags