.gitignore

factorygirl*
new*
Gemfile.lock

.ruby-gemset

factory_girl_benchmarks

.ruby-version

ruby-2.0.0-p353@rubytesting

benchmark.rb

#!/usr/bin/ruby

require 'factory_girl'
require 'perftools'
require 'benchmark'

class SomeObject; end

FactoryGirl.define do
  factory :some_object do
  end
end

TIMES = 100_000

Benchmark.bm do |bm|
  bm.report 'FactoryGirl.build' do
    PerfTools::CpuProfiler.start("factorygirl") do
      TIMES.times { FactoryGirl.build :some_object }
    end
  end

  bm.report 'new' do
    PerfTools::CpuProfiler.start("new") do
      TIMES.times { SomeObject.new }
    end
  end
end

Gemfile

source 'https://rubygems.org'

gem 'perftools.rb'
gem 'factory_girl'

results.txt

       user     system      total        real
FactoryGirl.buildPROFILE: interrupts/evictions/bytes = 633/0/32944
  6.850000   0.010000   6.860000 (  6.865386)
newPROFILE: interrupts/evictions/bytes = 2/0/168
  0.030000   0.010000   0.040000 (  0.029475)