bench.rb

require 'benchmark'
Benchmark.bm 10 do |x|
  x.report('=~'){    10000000.times{/a/ =~ 'a'; /b/ =~ 'a' }}
  x.report('==='){   10000000.times{/a/ === 'a'; /b/ === 'a' }}
  x.report('match'){ 10000000.times{/a/.match('a'); /b/.match('a') }}
  x.report('match?'){10000000.times{/a/.match?('a'); /b/.match?('a') }}
end

                 user     system      total        real
=~           5.040000   0.030000   5.070000 (  5.077508)
===          5.030000   0.000000   5.030000 (  5.033202)
match        5.840000   0.000000   5.840000 (  5.836059)
match?       1.670000   0.000000   1.670000 (  1.669442)

$ ruby -v
ruby 2.4.0preview2 (2016-09-09 trunk 56129) [x86_64-linux]