Custom date parser vs. Date.parse for Hyphenated ISO 8601 dates

date_parse_bm.rb

require 'date'
require 'benchmark/ips'

def custom_date_parse(str)
  Date.new(str[0,4].to_i, str[5,2].to_i, str[8,2].to_i)
end

Benchmark.ips do |x|
  x.time = 5
  x.warmup = 2

  x.report('Date.parse') do |count|
    count.times do
      Date.parse('2016-10-13')
    end
  end

  x.report('Custom parser') do |count|
    count.times do
      custom_date_parse('2016-10-13')
    end
  end

end

# $ ruby date_bm.rb
# Warming up --------------------------------------
#           Date.parse    16.088k i/100ms
#        Custom parser    77.894k i/100ms
# Calculating -------------------------------------
#           Date.parse    175.639k (± 2.6%) i/s -    884.840k in   5.041341s
#        Custom parser      1.098M (± 2.8%) i/s -      5.530M in   5.041368s