Apple's PowerPC partner, IBM, has revealed details of its multi-gigahertz Power4 ‘gigaprocessor’ - a cousin of the G4 chips that currently run the high-end Power Macs.

Continuing IBM's implementation of copper technology in the PowerPC architecture, the Power4 chip will feature all-copper interconnects and will be built on silicon-on-insulator (SOI) wafers, therefore combining high speed with reduced power consumption and dissipation.

Each chip contains more than one mile of copper wiring, 170 million transistors and uses two independent 1GHz microprocessors and a second-level (L2) cache. According to IBM, copper delivers high performance, being a better conductor than aluminium and can sustain higher current for longer time without failing. Copper is almost impervious to electromigration.

IBM aims to get "the system to work more efficiently, and not just to get the processor to run faster’. The focus has been memory bandwidth and data traffic. Instead of using one very large processor, Power4 uses two smaller CPUs with a shared L2 cache. The result is more efficient data sharing. The bandwidth capacity of the bus between L2 cache and the microprocessors is more than 100GB per second, or equal to relaying 20 full-length movies in one second, IBM said.

The Power4 will not be used in Macs, with IBM using it in its own AS/400 and RS/6000 workstations and servers. The Power4 microprocessor is designed to allow servers to handle the increasing loads of data traffic generated by Internet and e-business demand.

Test devices have been made. Production will begin in Q1 2000, with first systems due in the second half of 2000.