The chips in question are a 16 core monstrosity that has been benchmarked in Cinebench R15 running at 4.2 GHz and a 12 core speed demon with a 5.0GHz boost clock that the company has been showing around to motherboard makers.
If the leak is to be believed, this 16 core running at 4.2 GHz on all cores scored 4278 points in Cinebench R15. To put that into perspective an 8 core Ryzen 7 2700X scores 1828 points. A 16 core Ryzen 7 1950X Threadripper scores 3055 points and Intel's 16 core i9 7960X scores 3163 points. In fact, it takes a core i9 7960X
overclocked to nearly 4.8 GHz to match the leaked 16 Core Ryzen 3000 chip at 4.2 GHz.
These results indicate that Zen 2 brings above 10% improvement in IPC in addition to higher clock speeds thanks to the 7nm process. Combine that with a doubling of cores, AMD's Ryzen 3000 series could easily deliver double the multi-core performance of their predecessors up and down the stack.