Dual and quad CPUs used to be defining features of PowerMac towers back in the PPC days. The competition might’ve had Pentium 4’s with much higher clockspeeds,

Dual and quad CPUs used to be defining features of PowerMac towers back in the PPC days. The competition might’ve had Pentium 4’s with much higher clockspeeds, but the PowerMac towers had multiple PPC G4s or G5s where most of the competition only had a single P3 or P4. The Intel Mac Pro’s that followed had options for multiple Xeons, but the multi core nature of everything from the C2D forward put a major damper on the demand for multi CPU configs.