Purported details of the AMD Ryzen 9 3900 processor have been posted on Twitter. The Ryzen 3000 series chip has not been officially announced yet, but it seems this particular SKU could be a 65-W TDP variant as opposed to the Ryzen 9 3900X with its 105 W TDP. The latest chip is expected to have 12 cores and 24 threads.
https://www.notebookcheck.net/Rumored-clock-rates-for-AMD-Ryzen-9-3900-surface-online.430356.0.html