Extreme bad performance on benchmarks for ruby1.8

[tario]

railsdev1@railsdev1-VirtualBox:~/projects/fastruby$ ruby benchmarks/benchmark.rb
user system total real
ruby 1.160000 0.000000 1.160000 ( 1.190070)
fastruby 10.050000 0.010000 10.060000 ( 10.181692)