Hi
One thing that IME makes a difference is -funbox-strict-fields. It's probably better to use pragmas for this, though. Another thing to consider is garbage collection RTS flags, those can sometimes make a big difference.
I _don't_ want to speed up a particular program by modifying it, I want to take a set of existing programs which are treated as black boxes, and compile them all with the same flags. I don't want to experiment to see which flags give the best particular result on a per program basis, or even for the benchmark as a whole, I just want to know what the "standard recommendation" is for people who want fast code but not to understand anything.
All this and more on the under-publicised Performance wiki, http://haskell.org/haskellwiki/Performance
It's a very good resource, and I've read it before :) Another way to treat my question is, the wiki says "Of course, if a GHC compiled program runs slower than the same program compiled with another Haskell compiler, then it's definitely a bug" - in this sentance what does the command line look like in the GHC compiled case? Thanks Neil