Ben Hermans of Hyperion commented those benchmarks within the comments of ANN as follows:

"At a 600 mhz G3 with on-die L2 cache and a 133 mhz FSB you might expect a much higher speed than with a 150-200 mhz 060. I would guess a 300 mhz as an absolute minimum. On current PPC cards the relevant benchmarks of petunia are slowed down by several facts:

• The 68k processor is stealing still some cycles simply because it's still "awake". Once it will be made completly slept this will result in a reasonable gain of performance.
• Dual processor architecture with context switches and cache flushes
• WarpOS is used and not Exec SG

• mame.zip (4,5 M) - it's a .lha file with a .zip extension
• neomame.zip (800K) - it's a .lha file with a .zip extension