As an update I saw that the original post was about finding all the solutions to the problem, compared to the single first solution searched for above. Running

As an update I saw that the original post was about finding all the solutions to the problem, compared to the single first solution searched for above. Running for finding all solutions, I got the following timings (same computer as above, same settings, default consistency). n time search tree solutions 8 0.8752 ms 767 92 10 14.2759 ms 11431 724 12 306.7616 ms 232163 14200 14 8782.4620 ms 6391931 365596 Downloading the c-versions from https://github.com/davidad/8queens/tree/%2Bc_comparison https://github.com/davidad/8queens/tree/%2Bc_comparison gives a reference-time using the time built-in command of around 750 ms for 10k iterations. This means that the C solver takes around 0.075 ms per iteration which is a factor of ten faster than the Gecode version. That is not unreasonable given that the Gecode version is a high-level model in a general framework. I did not manage to build the assembly-version unfortunately. EDIT: Updated the timings and comments of the C-solver to represent that it actually solved the problem 10k times. Lesson, never do benchmarks quickly :-)