Macworld does some G5/Xeon comparing in an article about the Mac Pro chip. “With the Xeon 5100, Intel claims that it has eliminated one huge performance advantage held by the PowerPC architecture: vector processing. Known to Mac users as AltiVec, or the Velocity Engine, this technology increased vector-based processing significantly on the PowerPC machines, and was one of the reasons that applications like Photoshop were able to manipulate such large image files with ease, even when other parts of the Mac subsystem weren’t as fast as comparable Intel-based PCs.” More …