string vs integer palindrome benchmarks

palindrome.rb

require 'benchmark'

def int_pal?(num)
  n = num
  reverse = 0
  while (num > 0)
    dig = num % 10
    reverse = reverse * 10 + dig
    num = num / 10
  end
  return n == reverse
end

def string_pal?(num)
  s = num.to_s
  s == s.reverse
end

Benchmark.bmbm do |bm|
  bm.report("Integer palindrome method"){ (1...10000000).each{|x| int_pal?(x)} }
  bm.report("String palindrome method"){ (1...10000000).each{|x| string_pal?(x)} }
end

=begin
Rehearsal -------------------------------------------------------------
Integer palindrome method   7.700000   0.000000   7.700000 (  7.705190)
String palindrome method    4.890000   0.010000   4.900000 (  4.907374)
--------------------------------------------------- total: 12.600000sec

                                user     system      total        real
Integer palindrome method   7.770000   0.000000   7.770000 (  7.773088)
String palindrome method    4.720000   0.010000   4.730000 (  4.726223)
=end

this is slightly faster than my previous snippet, but it's still slower than your original int_pal?

def int_pal?(num)
  size = (Math.log10 num).floor
  pow1, pow2 = 1, 10**size
  (size/2.0).ceil.times do
    if num / pow1 % 10 != num / pow2 % 10
      return false
    end
    pow1 *= 10
    pow2 /= 10
  end
  return true
end