AMD will soon be releasing it's six core Phenom II X6 CPUs, codenamed "Thuban". The processors are very similar to "Istanbul" based Opterons that have been on the market for more than 9 months now. Together with "Thuban" six-core processsors also come Phenom II X4 "T" processors, codenamed "Zosma".
The Phenom II X6 will feature 6MB of L3 cache and six cores, together with a new feature that is similar to Intel's Turbo Boost technology, although the details aren't known yet.
What is currently more obscure are the new Phenom II X4 "T" processors. SiM industry sources close to us have indicated that the new processors will be based on the same cores as the Phenom II X6, so they likely can be unlocked in to full six cores - if you're lucky - and should feature the same 6MB of L3 cache and Turbo Boost like technology.
There will be two models available, Phenom II X4 960T running at 3.3GHz and the 940T running at around 3GHz. These clock speeds are without the Turbo functionality activated.
These new models will be available alongside some previous non-T Phenom II X4 models but will replace the aging Phenom II X4 965 in the high-end.
More details on pricing of these new CPUs as it becomes available.
Details about the 1000T series Phenom II X6 have been leaked earlier.
Update: Pricing and more details on the Turbo Core techonology.