In another extreme and probably impractical overclocking experiment, Intel's new top-of-the-line processor Core i9-12900K has hit clock frequencies of up to 8 GHz with a nitrogen cooling configuration.
https://www.notebookcheck.net/Intel-s-new-Alder-Lake-flagship-CPU-Core-i9-12900K-has-been-overclocked-to-8-GHz.577226.0.html