1ghz G3 from IBM
Per this MacCentral article, IBM announced their new 750FX PPC Processor yesteday:
The overall goal of the 750FX is to optimize system performance. In addition to doubling the L2 cache size to 512KB from the 750CX's and 750CXe's L2 cache size of 256KB, IBM also doubled the peak system bus speed to 200MHz. IBM and two of its partner developers, Tundra Semiconductor and Marvell Technologies, are developing controller chips to take advantage of the faster bus. In addition to making the bus faster, IBM has also improved the bus efficiency to provide 25 percent greater bandwidth.
This is the first PowerPC to use SOI and a low-K dielectric compound in tandem to increase performance and reduce power consumption.