From: winter heat Date: 2010-11-01T15:01:56+09:00 Subject: Why Ruby 1.9.2 double the speed on 2.53GHz vs 2.2GHz Core 2 Duo? The following program will take 3.6 seconds to run on a Macbook that has 2.2GHz Core 2 Duo, and 1.8 seconds to run on a Macbook Pro that has 2.53GHz Core 2 Duo. That's a bit weird... why doubling the speed when the CPU is only 15% faster in clock speed? I double checked the CPU meter to make sure none of the 2 cores are in 100% usage (so as to see the CPU is not busy running something else). Could it be because one is Mac OS X Leopard and one is Mac OS X Snow Leopard (64 bit)? Both are running Ruby 1.9.2. ------------------------------------------------------------ p RUBY_VERSION p RUBY_DESCRIPTION if defined? RUBY_DESCRIPTION n = 9_999_999 p n t = 0; 1.upto(n) {|i| t += i if i%3==0 || i%5==0}; p t ------------------------------------------------------------ 2.2GHz Core 2 Duo $ time ruby 1.rb "1.9.2" "ruby 1.9.2p0 (2010-08-18 revision 29036) [i386-darwin9.8.0]" 9999999 23333331666668 real 0m3.784s user 0m3.751s sys 0m0.021s ------------------------------------------------------------ 2.53GHz Intel Core 2 Duo $ time ruby 1.rb "1.9.2" "ruby 1.9.2p0 (2010-08-18 revision 29036) [x86_64-darwin10.4.0]" 9999999 23333331666668 real 0m1.893s user 0m1.809s sys 0m0.012s ------------------------------------------------------------ Test run on Windows 7: time_start = Time.now p RUBY_VERSION p RUBY_DESCRIPTION if defined? RUBY_DESCRIPTION n = 9_999_999 p n t = 0; 1.upto(n) {|i| t += i if i%3==0 || i%5==0}; p t print "Took #{Time.now - time_start} seconds to run\n" ------------------------------------------------------------ Intel Q6600 Quad Core 2.4GHz running Windows 7, 64-bit C:\> ruby try.rb "1.9.2" "ruby 1.9.2p0 (2010-08-18) [i386-mingw32]" 9999999 23333331666668 Took 3.248186 seconds to run ------------------------------------------------------------ Intel 920 i7 2.67GHz running Windows 7, 64-bit C:\> ruby try.rb "1.9.2" "ruby 1.9.2p0 (2010-08-18) [i386-mingw32]" 9999999 23333331666668 Took 2.044117 seconds to run ------------------------------------------------------------ it is also strange why an i7 with 2.67GHz is slower than a 2.53GHz Core 2 Duo. -- Posted via http://www.ruby-forum.com/.