Benchmark of the ruby Time class.

time_benchmark.rb

require 'time'
require 'benchmark'

max = (ARGV.shift || 100000).to_i

puts "# of iterations = #{max}"

Benchmark::bm(20) do |x|
  x.report("Time.parse") do
    (0..max).each do
      Time.parse("2010-08-15 00:00:00 UTC").to_i
    end
  end

  x.report("Time.utc") do
    (0..max).each do
      Time.utc(2010, 8, 15).to_i
    end
  end
end

On a Core i7

# of iterations = 100000
                          user     system      total        real
Time.parse            9.140000   0.010000   9.150000 (  9.161342)
Time.utc              0.310000   0.000000   0.310000 (  0.311067)

On an Arm7

# of iterations = 100000
                           user     system      total        real
Time.parse            45.760000   4.230000  49.990000 ( 50.027684)
Time.utc               3.440000   2.720000   6.160000 (  6.157313)