I just did some benchmarks for a fibonnacci(32) for some languages and different Neko runtimes, and here's some comparisons (time in seconds) :

• ocaml bytecode : 0.42
• ocaml opt : 0.06
• java -Xint : 0.73
• java JIT : 0.11
• MTSVM : 2.03
• Python 2.4 : 5.83
• PHP 4.3.10 : 16.40
• neko interp : 16.08
• neko ocamlgen bytecode : 9.90
• neko ocamlgen opt : 0.65
• neko VM : 1.91

Theses times only measure computation time and does not take into account VM startup or bytecode loading. I hope to get around a 10 factor improvement when adding JIT to Neko. That would bring us ahead of the OCaml bytecode speed which is quite good for a dynamically typed language with untrusted bytecode. Adding some primitives such as

$iadd

or

$icompare

for optimized integer operations might improve a lot also, but will only be available for high level statically typed programming languages that generate to Neko.