AMD claims that in internal testing, with exotic cooling methods, the 45nm based processor was able to reach speeds as high as 7GHz. Third-party sites were somewhat able to confirm this, with certain users able to reach 6.7GHz. Completely impractical for the ordinary user or even an enthusiast, but definitely indicative of where AMD can go with this architecture. AMD has also stated that the new Phenom II X4 955 can be overclocked to 3.8GHz using the stock fan unit. In our tests however we hit a ceiling of 3.7GHz and that was using a high performance after-market cooler.
AMD still has ground to cover as they've been unable to go head to head against Core i7 chips so far. That said, offering good value in the mainstream sector should be more than enough to keep the afloat, especially with their recent practice of reusing the AM2+ platform and giving legacy AMD users a solid upgrade path, unlike Intel.