It has been confirmed that it was one of AMD's new Matisse desktop processors that smashed its way through Geekbench's multi-core test recently; more precisely it was a Ryzen 9 3950X engineering sample (ES). Apparently, the system featured an overclocked CPU utilizing an AIO water cooler and an X470 reference motherboard.
https://www.notebookcheck.net/AMD-Ryzen-9-3950X-ES-confirmed-as-Geekbench-wrecking-record-breaker.424798.0.html
This is not best 16 core result.
Can find better one at GB4
Like this
browser[.]geekbench[.]com/v4/cpu/13546057
"Geekbench entries can be tampered with, but thanks to an HWBOT submission, this particular record appears to be genuine."
R9 3950X submission is 1st place on the HWBOT charts.
And the score was accomplished with an engineer sample of this CPU with a base clock of 3.3 and a boost clock of 4.3. The specs for 3950x announced by AMD include a base clock of 3.5 and a boost clock of 4.7, so I'm guessing that it's single core performance will be closer to that of an 9900k.