Used https://github.com/dakull/ruby-simple-benchmarks/ for benchmarking
> ruby --version
ruby 2.1.0p0 (2013-12-25 revision 44422) [x86_64-linux]
> time ruby bm_gc_mb.rb
user system total real
0.200000 0.010000 0.210000 ( 0.208676)