DailyTech writes AMD already has plans for 12-core processors:
"Don't be disappointed, AMD is making up for it," hints one engineer. Further conversations revealed that inter-CPU communication is going to be a big deal with the 45nm refresh. The first breadcrumb comes with a new "native six-core" Shanghai derivative, currently codenamed Istanbul. This processor is clearly targeted at Intel's recently announced six-core, 45nm Dunnington processor.
But sextuple-core processors have been done, or at least we'll see the first ones this year. The real neat stuff comes a few months after, where AMD will finally ditch the "native-core" rhetoric. Two separate reports sent to DailyTech from AMD partners indicate that Shanghai and its derivatives will also get twin-die per package treatment.
AMD planned twin-die configurations as far back as the K8 architecture, though abandoned those efforts. The company never explained why those processors were nixed, but just weeks later "native quad-core" became a major marketing campaign for the AMD in anticipation of Barcelona.
A twin-die Istanbul processor could enable 12 cores in a single package. Each of these cores will communicate to each other via the now-enabled HT3.0 interconnect on the processor.
The rabbit hole gets deeper. Since each of these processors will contain a dual-channel memory controller, a single-core can emulate quad-channel memory functions by accessing the other dual-channel memory controller on the same socket. This move is likely a preemptive strike against Intel's Nehalem tri-channel memory controller.