Slashdot | Is Mac OS X Slow?: "Actually, the kernel is slow. In lmbench (which measures the speed of basic UNIX kernel operations) OS X is half the speed of Linux. And the Velocity engine would be great...if the G4 had enough front side bus bandwidth to actually feed it. The AltiVec units themselves are very high quality, but because the average P4 has 3x the memory bandwidth (and streaming SIMD operations are *very* memory bandwidth dependent) it can't shine in the current G4."