The Intel Core i7-9850H is a high-end processor for laptops with six cores based on the Coffee Lake architecture (2019 refresh, CFL-HR). The processor clocks at between 2.6 and 4.6 GHz (4 GHz with 6 cores) and can execute up to twelve threads simultaneously thanks to Hyper-Threading. According to Intel, the CPU is manufactured in an improved 14nm (14nm++) process. Compared to the predecessor, the Core i7-8850H, the 9850H offers only improved clock rates.
The Coffee Lake architecture is similar to Kaby Lake and differs only in the amount of cores (now six cores for the high end versions) and the improved 14nm process (14nm++ according to Intel).
Due to the two additional cores, performance has increased by almost 50% compared to a similar clocked Kaby Lake processor like the Core i7-7920HQ (3.1 - 4.1 GHz). Single-core performance has not improved since its Kaby Lake predecessor. Compared to the i7-8850H, the performance improved only slightly.
The integrated Intel UHD Graphics 630 iGPU is supposed to offer a slightly higher performance as its clock rate has been increased by 50 MHz (rumored). The architecture is identical to that of the Intel HD Graphics 630. We do expect a performance improvement, but as a low-end solution it will probably only display current games smoothly at reduced details - if at all.
Intel specifies the TDP with 45 watts and therefore the i7 is only suited for big laptops with good cooling solutions. Using cTDP-down, the CPU can also be configured to 35 Watt resulting in a reduced performance.