The Inquirer today writes the "Reverse Hyperthreading" technology from AMD doesn't exist:
AMD doesn't have any such technology. It would like to have it but even the upcoming K8L quad core won't be able to present a dual or quad core as a single core to the Operating system.
On the other hand AMD doesn’t not need such a architecture as the operating systems are getting used to a dual and later quad machines. It's just a dream that someone set afloat but AMD doesn't have such a architecture.