There are two Lisp implementations on www.spoj.pl. One is Clisp which is bytecode compiled and rather slow and the other is SBCL which compiles to machine code and is the implementation used by the OP.<p>It looks as if you only looked at the former as the later has an entry at 0.52 (as mentioned by another commenter.)<p>A note about Common Lisp implementations is that there are many of them, all with different performance specs ideal use cases. Some are considered very fast, such as SBCL and CCL, others, not so much. Most of the data I've seen benchmarking Lisp against other languages uses one of the open source implementations. I'd like to see how a commercial Lisp, such as Allegro or Lispworks, performed, especially since those are the ones that have actually been worked on since the 80s/