The original discussion is here, and the description of the rumoured chip is as follows:
The IBM PowerPC 970MP RISC Microprocessor is a dual-core, 64-bit implementation of the IBM PowerPC ® family of reduced instruction set computer (RISC) microprocessors that are based on the PowerPCNo mention is made of an integrated memory controller. An integrated memory controller is something many have been predicting for the next generation G5, but for a desktop it may not really be necessary. It may be more desirable for laptops however, to reduce overall power consumption.
Architecture. This dual microprocessor, also called the PowerPC 970MP, includes a Vector/SIMD facility which supports high-bandwidth data processing and compute-intensive operations. The 970MP is also designed to support multiple system organizations, including desktop and low-end server applications, up through 4-way SMP configurations.
Note: The IBM PowerPC 970MP incorporates two complete microprocessors on a single chip, along with some common logic to connect these microprocessors to a system.