Desktop processors Intel Core of the latest ninth generation unofficially support memory of the outdated DDR3 standard. The Japanese enthusiast @momomo_us managed to figure it out.
Screenshots from CPU-Z
In support of his discovery, the user assembled a computer based on an Onda H310C-SD3 motherboard with a Intel Core i5-9600K chip and two DDR3-1333 RAM modules. To get the motherboard to work with the Intel Coffee Lake-S Refresh processor, the Japanese had to modify B IOS.
Recall that the DDR3 specification was introduced in 2007, and in 2014 it was replaced by DDR4.