Bench

bench.rb

require 'benchmark'

n = 100_000_000
Benchmark.bm do |x|
  x.report do
    result = []
    row = nil
    n.times do |i|
      row = i * 5
      result << row
    end
  end

  x.report do
    result = []
    n.times do |i|
      row = i * 5
      result << row
    end
  end

end

results

       user     system      total        real
   7.510000   0.220000   7.730000 (  7.794392)
   7.550000   0.210000   7.760000 (  7.765262)