Last week we published Ubuntu 7.04 to 8.10 benchmarks from a Lenovo ThinkPad T60 and had found Ubuntu's performance degraded peculiarly over the past year and a half. We then published Fedora 7 to 10 benchmarks covering the same time-frame and from the same exact Intel notebook computer, but the newer releases of Fedora were only marginally slower in a few tests. In our performance exploration of Ubuntu we now have additional tests to publish this morning. This time around we're switching out the hardware we're testing on to Intel's newer Core 2 series and we're comparing the performance of the x86 and x86_64 editions of Ubuntu 8.10 against Apple's Mac OS X 10.5.5 operating system.