VideoCardz noticed AMD's Ryzen 5 5800U popped up in the Geekbench database. This Zen 3-based "Cezanne" processor is listed with a 1.9GHz base clock and a 4.4GHz Boost. Previous rumors pointed to a 2.0GHz base clock so it's unknown whether this is a wrong readout or if the specifications have changed. Single-threaded performance of this eight-core chip seems quite a bit higher than the Ryzen 7 5700U:
The Ryzen 7 5800U appears to be 20% faster than Ryzen 7 5700U in a single-threaded benchmark, while only offering 2.6% improvement in the multi-threaded benchmark.