Hello Chris, Monday, January 23, 2006, 6:09:15 PM, you wrote: CK> Using -A400m I get 39s down from 55s. That is the best Data.HashTable time I CK> have seen. (Using -A10m and -A100m were a little slower). 1) "-A400m" is a bit unusual. "-H400m" for 500-meg machine, "-H800m" for 1g computer and so on will be fastest. current GHC doc leaks explanations in this area, but basically -H just allocates that much area and then dynamically changes -A after each GC allocating all available space to the generation-0 memory pool 2) it's better to say that was MUT and GC times in your program, and even better just to post its output with "+RTS -sstderr" please post improved results here. that's really interesting for me, and for my programs too ;) -- Best regards, Bulat mailto:bulatz@HotPOP.com