Much has been made over the past few days about IBM's unveiling of the POWER6 CPU. The CPU runs at 4.7 GHz per core, and IBM claims it doubles the speed of the POWER5 while using nearly the same amount of electricity to run and cool it. IBM also claims that the speed is also nearly three times faster than the latest Itanium processor made by Intel.
Such impressive specifications have lead some to question whether Apple made the right move by moving to Intel. It is important to note however, that the POWER6 is a mid to high-end server processor. Apple, Motorola, and IBM developed PowerPC from the POWER architecture to meet the desktop PC market. Apple used such chips in its systems, including the PowerPC 970 "G5", which was derived from IBM's POWER4.
POWER processors from IBM are utilized in markets that Apple has yet to venture into: mid to high-end servers. POWER gets most of its competition from Sun's UltraSPARC and Intel's Itanium rather than low to mid-range x86-based servers, which typically use Intel Xeon or AMD Opteron processors.
Additional Reading:
POWER Architecture
PowerPC Architecture
SPARC Architecture
IA-64, aka Intel Itanium