Hi, I've recently implemented some benchmarks for my library, and while I expected a slowdown for 64-bit code, I'm a bit bit surprised by the results. In summary: with 64 bit ghc 6.6.1, my benchmark runs in ~160 seconds with 32 bit ghc 6.6, it runs in ~ 95 seconds Most of the time is traversing a list of elements, doing a few numerical calculations. Presumably this is due to increased code size due to 8-byte pointers? I'll add some more benchmarks, but just wondered whether this was to be expeced, and, if so, whether I perhaps should be running a 32 bit version of GHC? I tried to Google for other benchmark results, but couldn't find any. Are there any particular GHC options I should use for compiling 64-bit code? I'll install 6.8 RSN, perhaps that will improve things? Oh, and if anybody wants to play with it, it should be possible to install Data.Binary and HXT, and then: darcs get http://malde.org/~ketil/bio cd bio make bench -k -- If I haven't seen further, it is by standing in the footprints of giants