Several recent Ryzen 5 1600X CPUs owners built new systems and upon booting to windows for the first time were shocked to discover that they had 8 cores and 16 threads. The CPUs had the same 3.6GHz base clock and 4.0GHz Turbo of the 1600X, but had 8 cores and 16 threads instead of 6 and 12 respectively. Making them effectively price-cut 1800X CPUs.
Others reported the same with the cheaper Ryzen 5 1600 CPUs. All of the unlocked chips were manufactured on the 36th week of 2017 in Malaysia. You can decode your CPU’s batch code with this handy guide, made by redditor rigred, to find out if it was part of the same batch.