Well, it seems that XBench screwed up and sent out a fix. Here's what got fixed:

Corrected a mistake that caused the altivec test to be turned off on PowerPC machines

Turned off coalesced graphics updates for all platforms on Mac OS 10.4.4 and higher

Switched compiler to GCC 4.0 on PowerPC. This provides some boost to floating point and AltiVec scores, and these have been recalibrated accordingly. This also raises Xbench's system requirements to 10.3.9 or higher.

Revised machine database to include the MacBook, Intel iMac and several other models

Added code to dynamically load machine database on launch from the Xbench website

Added support for temporarily turning off beam sync on Tiger while running graphics tests

Fixed an issue that causes Xbench to fail to launch on Leopard

Built with Xcode 2.4