Technology for a notebook version of the PowerPC G5, aka the PowerPC 970
series of processors, may be at hand. The PowerPC 970FX chip used in Apple’s
Power Mac G5 desktops and Xserve servers can also be used comfortably within
future PowerBook notebooks through a power-management technique called "PowerTune."

G5 PowerTune design is based on a single PLL that can shift the processor
into several low-power states in a single clock cycle. The PLL will be locked to
a single frequency, simplifying the synchronization of circuitry. Instead, a
multiplexer will divide the bus speed, thus slowing the chip. This scheme is the
opposite of desktop processors, where the processor often runs at some greater
multiple of a given bus speed. The frequency switch will not be limited to the
processor core but also manage the processor bus, the I/O bridge and the memory
controller.

The portable-space specs that are out there talk about 15 to 30 watts for
maximum power. The low-frequency operating conditions in the idle state—nap—are
in the 1- to 2-watt range. A PowerPC 970FX in the 1/64 "deep nap" state could
run at 30MHz, which would equate to about 1.9GHz in full-speed mode. PPC
970FX-based notebook is not expected to ship before the end of the year.

Technology for a notebook version of the PowerPC G5, aka the PowerPC 970
series of processors, may be at hand. The PowerPC 970FX chip used in Apple’s
Power Mac G5 desktops and Xserve servers can also be used comfortably within
future PowerBook notebooks through a power-management technique called "PowerTune."

G5 PowerTune design is based on a single PLL that can shift the processor
into several low-power states in a single clock cycle. The PLL will be locked to
a single frequency, simplifying the synchronization of circuitry. Instead, a
multiplexer will divide the bus speed, thus slowing the chip. This scheme is the
opposite of desktop processors, where the processor often runs at some greater
multiple of a given bus speed. The frequency switch will not be limited to the
processor core but also manage the processor bus, the I/O bridge and the memory
controller.

The portable-space specs that are out there talk about 15 to 30 watts for
maximum power. The low-frequency operating conditions in the idle state—nap—are
in the 1- to 2-watt range. A PowerPC 970FX in the 1/64 "deep nap" state could
run at 30MHz, which would equate to about 1.9GHz in full-speed mode. PPC
970FX-based notebook is not expected to ship before the end of the year.