gistfile1.rb

#!/usr/bin/env ruby
require 'benchmark'

Benchmark.bm do|b|
  b.report("block") do
    (1..1000000).map {|n| Math.log(n) }
  end

  b.report("to_proc") do
    (1..1000000).map &Math.method(:log)
  end
end

__END__

      user     system      total        real
block  1.200000   0.070000   1.270000 (  1.280115)
to_proc  1.430000   0.030000   1.460000 (  1.461956)