An overclocked AMD Radeon RX 5700 XT can give good competition to an NVIDIA GeForce RTX 2080 in synthetic benchmarks as was discovered by a Redditor who managed to crank up the 5700 XT all the way to 2.1 GHz. At this frequency, the 5700 XT scored higher than the RTX 2080 FE in Fire Strike Ultra indicating that the RDNA architecture has good potential for overclocking.
https://www.notebookcheck.net/AMD-Radeon-RX-5700-XT-OC-manages-to-beat-the-NVIDIA-RTX-2080-in-Fire-Strike-Ultra-shows-RDNA-has-good-overclocking-potential.428050.0.html