Our measurements show that Dirt 5 is longing for a potent graphics card. Read in this article which model it should be for certain settings and resolutions.
https://www.notebookcheck.net/Dirt-5-Laptop-and-Desktop-Benchmarks.503929.0.html
I tested my laptop using the ultra high settings.
Laptop: HP Pavilion Gaming 15-ec1026la, upgraded with a 8GB stick for dual channel.
CPU = Ryzen 5 4600H
RAM = 16GB DDR4 (8x2) @ 3200MHz CL22
GPU = GTX 1650 4GB
And my results were:
Average FPS = 20.7 (25% higher)
Minimum FPS = 14.8 (23% higher)
Maximum FPS = 25.8 (no reference)
Low 0.1% FPS = 15.6 (25% higher)
Low 1% FPS = 17.8 (36% higher)
I think the results can be explained for the different CPU, because all other specs were practically the same.
Also, for High and Medium settings my average results are
High: 35.7 FPS (0.6% higher)
Medium: 50.1 FPS (5% higher).