I was looking at the IBM PowerPC webpage, and I noticed an article about RapidIO. According to rumor (and according to both IBM and Motorola's PPC roadmaps) the G5 will use RapidIO. What was interesting is that the article said (if I understood it correctly) that RapidIO buses ran at four clock speeds: 125MHz, 250MHz, 500MHz, and 1GHz. So, if I understand this correctly, the G5 will have to have a bus at one of those four speeds. I *think* the top two (or at least the top one) speeds are theoretical because it seems unlikely that there would be that huge an increase in bus frequency. That leaves 125 and 250 Mhz. Since 125 would seem like a step down from the 133MHz bus on the G4 (emphasis on 'seem'), I would expect the 250MHz bus.
here's the article:
http://www-3.ibm.com/chips/products/powerpc/newsletter/apr2001/tech-feat.html
here's the article:
http://www-3.ibm.com/chips/products/powerpc/newsletter/apr2001/tech-feat.html