MacRumors.com

Appleinsider posted a small update today which claims that second generation PowerMac G5s would make an appearance by March 2004. The new machines are reported to have advanced features including 533 DDR II RAM support and up to 1.5GHz bus as well as the incorporation of 90nm G5s and "Power Tune" technology.

As previously reported, IBM will be presenting 90nm PowerPC 970 technology at the ISSCC in Feb 2004. First reference to "PowerTune" was seen in the advance program (PDF) where it is briefly described under "PowerTune: Advanced Frequency and Power Scaling on 64b PowerPC Microprocessor" (Page 59)

PowerTune is a power-management technique for a multi-gigahertz superscalar 64b PowerPC processor in a 90nm technology. This paper discusses the challenges and implementation of a dynamically controlled clock frequency with noise suppression as well as a synchronization circuit for a multi-processor system.

It's not completely clear how these 90nm G5 machines would fit with Appleinsider's previous claim that PowerMacs would see revisions in January 2004.