I did a build time test with hackage.haskell.org/package/bloodhound today. I tested 8.2 (RC), 8.0, 7.10, and 7.8. I used Bloodhound in part because it has very few but very large modules which is sort of a pathological case for GHC right now. I first built the deps and library with each compilers and then reran the build once or twice until the results stabilized. The build re-built the V5/Types module and the examples depending on that module. I triggered a build by adding/removing newline characters in the V5/Types module. I've pushed the build targets / stack.yamls to the git repository: https://github.com/bitemyapp/bloodhound Here are the results: 8.2 build: 126.37s user 2.26s system 101% cpu 2:07.16 total 8.0 build: 147.44s user 2.24s system 100% cpu 2:28.93 total 7.10 build: 163.38s user 2.14s system 100% cpu 2:44.64 total 7.8 build: 129.12s user 2.30s system 101% cpu 2:10.09 total Please let me know if you have any questions. -- Chris Allen Currently working on http://haskellbook.com