While this is still an engineering sample, and should not be considered as a final clock, it does show that AMD will be able to pull some impressive frequencies on its upcoming 3rd gen Ryzen CPUs.
TUM_APISAK revealed these numbers on its Twitter account, and, of course, the leak does not include any TDP or other details, and it is likely that other and this SKU will end up with much higher clocks, like the rumored 8-core or 12-core SKUs.
Zen2 ES 16 Core— APISAK (@TUM_APISAK) May 9, 2019
Base clock 3.3 Ghzฺ
Boost clock 4.2 Ghz
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The big part of AMD's Computex 2019 show will be about the Zen 2 architecture and new Ryzen 3rd gen CPUs, with a possible launch in July. Most motherboard makers are already teasing their new motherboards and you can expect more details once Computex 2019 kicks off on May 28th.