Redmine

require 'benchmark/ips'
Benchmark.ips do |x|
  x.report('casecmp') { 'PostgreSql'.casecmp('postgresql') == 0 }
  x.report('match')   { 'PostgreSql' =~ /postgresql/i }
  x.report('match?')  { 'PostgreSql'.match? /postgresql/i }
  x.compare!
end

Comparsion:
casecmp:  4218477.8 i/s
 match?:  3025829.3 i/s - 1.39x  slower
  match:  2222223.1 i/s - 1.90x  slower