benchmark.rb

require 'benchmark'

N      =  1000000
fixnum =  1234567
string = 'abcdefg'

Benchmark.bm(11) do |x|
  x.report 'Fixnum#to_s' do
    (1..N).each { fixnum.to_s }
  end

  x.report '"#{Fixnum}"' do
    (1..N).each { "#{fixnum}" }
  end

  x.report 'String#to_s' do
    (1..N).each { string.to_s }
  end

  x.report '"#{String}"' do
    (1..N).each { "#{string}" }
  end
end

=begin
                  user     system      total        real
Fixnum#to_s   0.220000   0.000000   0.220000 (  0.229589)
"#{Fixnum}"   0.320000   0.000000   0.320000 (  0.326202)
String#to_s   0.070000   0.000000   0.070000 (  0.072514)
"#{String}"   0.130000   0.000000   0.130000 (  0.132092)
=end