ZD Net writes about their experience of running the x86 version of Apple's Mac OS X on a normal x86 computer. For the test they used the Toshiba Portege M300 notebook..
All of which makes the current test results for Mac OS X x86 more remarkable. Clearly, essential components of the power-saving functions in the Pentium M processor (in our testbed Toshiba Portégé M300) are already supported. There can be no other explanation for the fact that the power consumption of Mac OS X x86 is on a par with Windows XP running on the same notebook computer. Mac OS X is even a little faster than Windows XP at starting up, while the two operating systems shut down at about the same speed. As far as resource hunger is concerned, Apple's OS is a little less demanding: after loading, Mac OS X x86 leaves 324MB of RAM out of 512MB free, while XP releases only 290MB.You can check out the full article over here.