benchmark_to_json_vs_multi_json.rb

require 'benchmark/ips'
require 'json'
require 'oj'
require 'multi_json'

Benchmark.ips do |x|
  hash = 100.times.inject(Hash.new) {|h, i| h["key#{i}"] = i; h}
  x.report('to_json') do
    hash.to_json
  end
  x.report('MultiJson') do
    MultiJson.dump hash
  end
  x.compare!
end

result.txt

Warming up --------------------------------------
             to_json     2.206k i/100ms
           MultiJson     9.762k i/100ms
Calculating -------------------------------------
             to_json     22.540k (± 7.0%) i/s -    112.506k in   5.017223s
           MultiJson    102.093k (± 9.8%) i/s -    507.624k in   5.046538s

Comparison:
           MultiJson:   102093.5 i/s
             to_json:    22540.3 i/s - 4.53x slower