The Ryzen 9 4900HS chip comes in a 35 watt package (the slightly more powerful 4900H consumes 45 watts). However, AMD said that the chips deliver up to double the performance per watt compared to the 2nd-generation 12-nanometer chips, thanks to improvements in both the manufacturing technology and architecture. AMD said that the chips can also idle to lower power states and back to full power more quickly and "reduce the penalty of power state transitions."
AMD's platform control also makes the processors more efficient at distributing loads between the discreet graphics and processor. As a result, notebooks running AMD's 4000 H-series chips like the ASUS ROG Zephyrus Z14 will be able do up to 10 hours of video playback and let you game for longer, too.
AMD promised that the 4000 H-series Ryzen chips will arrive sometime in spring 2020, so we should see ASUS's ROG Zephyrus G14 laptop with Ryzen 4000 HS graphics around the same time. There's no word yet on any pricing nor an exact date, however, and coronavirus problems around the world could push back potential release dates.