This was a problem on most Macs of the era. The ATi Rage chips used in most Macs of the time was not powerful enough for Quake III. They were ok for less intens

This was a problem on most Macs of the era. The ATi Rage chips used in most Macs of the time was not powerful enough for Quake III. They were ok for less intense games but Q3 was pushing the envelope.