Being that this is just a rumor followed by speculation, take all of this with a grain of salt.
The first bit of news is that Intel is apparently considering an entry-level Xeon platform that would get rid of FB-DIMMs. FB-DIMMs have their good uses, but tend to be more expensive, run hotter, and have some latency penalties which can adversely affect the performance of some applications.
“FB-DIMMs consume quite a bit more power with commensurate heat (RAM fan is a necessity, not an option, on these), the AMB chip in there adds a bit of latency as well - although, with recent version, nearly the same as typical registered DIMM, and, well, these modules ain't cheap by any measure.
Even the brand new FBD-800 low-voltage DIMMs, while taking care of performance and power/heat issues, don't exactly solve the price problem.”
So the word on the street is that Intel is planning on making a registered DDR-2 series of chipsets for their Xeon lineup.
At first these are likely to be 1333MHz FSB chipsets, but could migrate to the upcoming 1600MHz FSB sometime in early '08. That's where the fun part of the speculation comes in: What will successors to Intel's V8 platform use?
While the V8 isn't a direct rival to the Quad FX, it is easy to see why many people like to compare the two. If Intel moves away from FB-DIMMs for the V8, it could encourage further comparison.