AMD has despite of high hopes from enthusiasts and overclockers not launched any quad-core processors based on the hexa-core Thuban circuit. However, so called Zosma processors have appeared at OEMs, sporting four cores and TurboCore technology.
TubroCore is a technology that is available only in AMD’s hexa-core circuits which is why Zosma is based on a hexa-core CPU with two cores deactivated. Hewlett-Packard has now started selling desktop PCs with two different Phenom II X4 models that can’t be found in retail.
AMD Phenom II X4 840T (2.9 GHz) and 960T (3.0 GHz) are both quad-core models with 2MB L2 cache, 6MB L3 cache and TurboCore support. The Zosma-based processors can in theory be unlocked to fully fledged six shooters, just like the AMD Phenom II X6 series.
Just like with all attempts to unlock processor cores there is a chance of failing and in this case there is no guarantee since it will be hard to get a hold of the processor fo systematic testing.
AMD most likely does not want to undermine the sales of its Phenom II X6 processors and still be able to move what might be slightly defect hexa-core chips as quad-cores instead.