A clock rate of 2,940.0 MHz has been recorded for a customized GeForce RTX 2080 Ti graphics card. The hardware was specially prepared as part of the Galax OC Gathering 2019. The incredible clock rate was measured as part of a GPUPI 1B benchmark test, which also resulted in the system achieving a very credible mark of 2 s 691 ms.
https://www.notebookcheck.net/Overclocked-GeForce-RTX-2080-Ti-pushed-to-astonishing-clock-rate-of-2-94-GHz.415780.0.html