Although this feat has been achieved using ice cubes in an improvised hardware setup that cannot run for long periods under the record-breaking frequency of almost 5 GHz, it is worth mentioning that the AMD Ryzen 7 4700G Renoir APU has been pushed all the way up to 4.96 GHz across all cores.
https://www.notebookcheck.net/AMD-Ryzen-7-4700G-Renoir-pushed-to-4-96-GHz-across-all-cores.482485.0.html