Performance: Mac vs Windows, PowerPC vs Intel

At my house I have three Macs. A 3.5 year old Powerbook 12" (OSX 10.4, 1Ghz G4 with 1.25 Gb of RAM) that has been through the wars, has a failed optical drive and is covered in bumps and bruises. This is my day to day machine, my workhorse. Plus I have a relatively new Mac Mini (OSX 10.4, 1.7 Ghz Core Duo with 1 Gb of RAM) - actually this is the wife's. And my favourite of the lot - a 1999 iMac G3 (OSX 10.3, 500 Mhz with 512 Mb of RAM) - which has been pretty much relegated to being a DVD player for my daughter (although every time I see it I want it back for myself - running OS9 with a Finder that works).

As I say, the Powerbook is what I use for work. But the other day I ended up working from home, and remembering DHH's post about how fast his (then) brand-new MacBook Pro was, I thought it would be worth putting the Mini through its paces. My application is starting to creak a bit on the testing front on the Powerbook - 12 seconds for the unit tests, 50-60 seconds for the functional. So I spent an hour or so installing various bits of software, did an svn co and typed rake. 2 seconds for the unit tests and 11 seconds for the functionals! Incredible. I couldn't believe it.

So I thought I'd give the Dell desktop I have in the office a run out too. That runs Windows XP SP2 and has 1Gb of RAM and a 3Ghz P4 in it (that Task Manager reports as dual-core). A while to install Rails ... oops, forgot to install MySql ... then Cmd.exe (erm, no Cmd-K) and rake ... unit tests 12 seconds, functional tests 27 seconds.

Obviously there are variables at work here. The Mini uses SATA drives, the Powerbook the significantly slower Ultra-ATA - I have no idea what the Dell uses. The Dell had Mysql 5, the Powerbook Mysql 4. The Dell is switched off every night. The Powerbook and the Mini have not been rebooted since 10.4.9 came out a few weeks ago. But what really struck me was that the old "Megahertz Myth" is true. A 1Ghz PPC chip is only slightly slower than a 3Ghz P4. What prompted the switch to Intel (apart from the obvious Parallels/Boot Camp/VMWare bonus) is the fact that Core Duo is SO much better.