The Guru of 3D published a review on the Core i9 12900K DDR4 3600 vs DDR5 5200 performance
A quote from the article:
Recently Intel released Alder Lake-based processor, the Core i9 12900K, and the platform is poised for the future with its incredibly fast performance paired with DDR5 memory, however works with DDR4 ...Core i9 12900K DDR4 3600 vs DDR5 5200 performance review