IBM has unveiled two new PowerPC chips. The move comes just one month after Big Blue's primary customer for its chips, Apple, announced plans to switch its allegiance Intel processors. The new PowerPC 970MP is a dual-core version of the PowerPC 970FX, known to Apple customers as the G5 processor, while a new low-power version of the PowerPC 970FX is destined for a laptops.

Manufacturing problems at IBM caused a delay in for the G5 processors last year, much to Apple's dismay, and power-consumption issues forced Apple to use liquid cooling in a high-end Power Mac and pull back on launching a G5 PowerBook or iBook. However, Apple won't be switching its entire range of Macs to Intel until 2007.

The PowerPC 970FX chip consumes around 13-Watts of power when running at 1.4GHz and 16-Watts when running at 1.6GHz, according to IBM. By comparison, Pentium M-based PCs have to handle around 27-Watts of power consumption. Comparing the processors is a little trickier mind due, because Intel publishes thermal design guidelines for PC manufacturers while IBM cites 'typical' power consumption. However, it's likely that the PowerPC 970FX chips will outperform Apple's current crop of G4-based iBooks and PowerBooks.

The two microprocessors cover a large frequency and power envelope using dynamic frequency and voltage scaling. This power-tuning allows you to quickly change the frequency from full frequency to f/2 and f/4 at a system level; for additional power savings, you can apply the resulting voltage reduction.

A power envelope shows the complete range of frequency and power available for the microprocessor. In addition to the full frequency power-tuning capabilities, the power-saving modes of doze, nap, and deep nap reduce the power envelope, allowing for a reduction of average power consumption.

As silicon technologies have scaled to smaller dimensions, the power of the processor has changed from solely AC switching power to a combination of leakage power and switching power. The implementation of the microprocessors in a 90nm technology reduces the switching power because of the reduction of capacitance due to chip size and a voltage reduction.

The subthreshold leakage current, which is a small amount of current from any transistor that is supposed to be turned off, increases dramatically at the smaller dimensions. In addition, 90nm technologies introduce a non-negligible amount of gate leakage power due to electrons tunnelling through the gate oxide of the transistor to the silicon.

BIOS, Jul 11, 05 | Print | Send | Comments (0) | Posted In Processor