According to a rumor started by Zolkorn.com and spotted by PCGamesHardware.de, AMD will not be able to deactivate half of the four-core Zen module, which means the lineup will only launch in quad- and eight-core models, with and without SMT (Simultaneous MultiThreading).
This new rumor contradicts some previous rumors that AMD Ryzen series will include a full lineup, including a dual-core (with two cores disabled) and six-core versions.
The same source suggests that AMD will have several SKUs with a difference in the number of cores, SMT, frequency and TDP, so there will still be plenty of CPUs to choose from.
More details should be coming soon as the expected launch is scheduled for March.