The following information is from an unconfirmed and anonymous source. As such, authenticity is always uncertain, but due to the content of the piece, was felt to be of sufficient interest for publishing. Of interest, MacBidouille has posted similar (but fewer) details in their unconfirmed rumors of the PPC's timeline. This information below may represent corroboration -- or simply a common source. Take, as with all rumors, with an appropriate amount of skepticism.
Apple and IBM have been working on parallel development of the Power5 and PPC 980. The PPC 980 is a single core version of the Power 5. While prototype forms of this chip exist, it is almost a year away from shipping in Macs.
Improvements in the PPC 980 include Hyperthreading, eLiza error correction, and more massive parallelism. IBM's implementation of hyperthreading provides a 30% gain over Intel's. eLiza technology will reduce the bottlenecks when the branch prediction unit fails. Altivec will split into 3 pipelines (vs 2 in the 970), 4 Integer and 4 Floating point units. 980 will have to be built on a 90nm processor due to heat dissipation requirements.
Steve's comment of 3GHz in 1 year will not be accomplished with the G5 (970) - which will top out at 2.6-2.8GHz. The PPC 980 will start at speeds of 2.6-3GHz and top out around 4.5-5GHz. The G5 will make its way into PowerBook lines in Jan/Feb, Xserve's later this year, and iMacs in approximately one year.
Marklar's project size has decreased, but remains ongoing. There are four generations of the PowerPC including and beyond the 970 that are in development and planning. Besides the 980 chips (targetted at end of 2004), there are plans for 990 chips on a 65nm process in 2005/2006 @ 6GHz and scaling up to near 10GHz. Beyond this, the PPC 9900 starting on a 45nm process is targetted in 2007/2008 starting at 9-10GHz and reaching up to 20-25GHz by 2010-2011.
