A few weeks back when Intel launched their Quad Core CPUs I talked a bit about the race between AMD and Intel on the quad core front and how it compared with the race to reach the dual core first distinction.

AMD is again showing off a CPU design that could prove to offer more performance than Intel can muster with its current quad core parts that are two dual core CPUs packaged on the same chip, whereas the AMD design puts all four cores on one die for greater performance.
AMD is still shooting for a mid 2007 launch for their quad core parts and expects to see a 70% gain in performance on their quad core Opteron series as compared to the AMD dual core CPUs. AMD also has an interesting video demo of the quad core CPUs online currently.