The AMD Ryzen 9 4900HS is a mobile SoC for big laptops based on the Renoir architecture. The 4900HS integrates all eight cores based on the Zen 2 microarchitecture. They are clocked at 3 (guaranteed base clock) to 4.3 GHz (Turbo) and support SMT / Hyperthreading (16 threads). The chip is manufactured in the modern 7 nm process at TSMC and partly thanks to it AMD advertises a 2x improved performance per Watt for the Renoir chips
According to our information, the Ryzen 9 4900HS is only slightly faster than the Ryzen 7 4800HS. The CPU is clocked 100 MHz (base and boost) higher, but the gains greatly depend on the cooling and TDP settings. Compared to Intel chips, the i9-9980HK top model should be comparable. That means the Ryzen 9 4900HS should be able to handle all demanding tasks and gaming. Compared to the similar named 45W-version, the Ryzen 9 4900H, the 4900HS is differs in 100 MHz boost and 300 MHz base clock.
In addition to the eight CPU cores, the APU also integrates a Radeon RX Vega 7 integrated graphics card with most likely 7 CUs. The dual channel memory controller supports DDR4-3200 and energy efficient LPDDR4-4266 RAM. Furthermore, 8 MB level 3 cache can be found on the chip. See our hub page on the Renoir Processors for more information.
The TDP of the APU is specified at 35 Watt (default). That means the chip is intended for big and relatively heavy laptops. The Ryzen 7 4900HS is the 35 Watt version of the R9 4900H with a 10 Watt lower TDP.