The second incarnation of that much joked about processor, the Itanium, has undergone a boost to bus speed, according to an announcement by Intel today.
For the first time, Itanium 2 processors have a 667 megahertz (MHz) front side bus (FSB), which connects and transfers data between the microprocessor, chipset and systems main memory. Servers designed to utilize the new bus are expected to deliver more than 65 percent greater system bandwidth over servers designed with current Itanium 2 processors with a 400 MHz FSB. This new capability will help set the stage for the forthcoming dual core Itanium processor, codenamed "Montecito," which will feature the same bus architecture.
Interesting to note that Intel refer to their dual core Itanium. You need a fatter bus if you increase CPU speed, or if you have multiple cores using the same bus - the faster the bus, the better it can satisfy the requirements of the processing units, to put it simply.

A 1.66GHz with 9MB cache will set you back a little over $4.5k if you're buying in quantities of a thousand.

Check out the press release for more info.