damned lies and benchmarks. hipe enabled? VM tuned properly? attempt to use halfword emulator? comparing C++ the compiler optimized down to SSE2 instructions to an emulator VM loop?
How much slower is Ruby than C++? Ruby runs every startup in the world. This website is the home of "DO THINGS THAT DON'T SCALE" including using fast to write programming languages at all costs even if 3 months later their "we have modules for every occasion!" design will be inadequate (you are testing your _ideas_ after all, not programming language speed, at least of the majority of use cases for people on this site).
a good candidate for writing a distributed server
distributed means you need monitoring. monitoring means you need supervision. supervision means you need restart strategies or failover or other promotion mechanisms. all that is built into erlang for free. optimize for _reliability_ not for speed when creating distributed systems.
If you'd looked at that web page you'd know the answer to "hipe enabled?"