I wrote in a previous article that the newest rev. B G5 2.0 GHz Power Mac was no longer using the older 130 nm G5 970 chip.
This has been confirmed. Typing "ioreg -l | grep cpu-version" in the Terminal yields an identical CPU ID in the new G5 2.0 as the G5 2.5, and both are different from the rev. A and apparently also different from the earliest rev. B G5 2.0 machines. Thus, all new rev. B machines (including likely the 1.8 GHz machines) seem to be utilizing the 90 nm 970FX chip.
Given that the new iMac G5 will also use this chip, there remains no machines in Apple's lineup that use the old 130 nm G5 970 chip. In other words, we have already moved completely to a new chip generation now, a year after the original G5 was introduced.
G5 970 RIP.
[Update August 18, 2004]
There seems to be some confusion about the CPU IDs mentioned in this article. To clarify, if you type "ioreg -l | grep cpu-version" on a new rev. B dual 2.0 you will get one of two numbers:
003c0300 - PowerPC G5 970FX (90 nm)
00390202 - PowerPC G5 970 (130 nm)
In other words, both of these chip types are found in rev. B dual G5 2.0 Power Macs. Even if you have the older (hotter) chip, don't worry. The speeds of the two chips are identical, and fortunately, reports are that the older chip still makes for a very quiet Power Mac as well, despite being a higher power chip.
Also, please note my later article about the rev. B G5 motherboard.