According to a submission on HWBOT.org, Newlife, an overclocker from Australia, managed to push G.Skill's Trident Z E-die 8GB memory (F4-3600C17-4GTZ) module to a DDR4 memory frequency of 2,039.6MHz, which is DDR4-4079. The module was pushed on a Gigabyte Aorus AX370-Gaming K7 motherboard with F4 BIOS and Ryzen 5 1400 CPU clocked down to 800MHz.
The memory module ended up working at 2,039.6MHz with 18-20-20-58-93-1 timings.
While this is not a world record, which is currently held by Toppc, with 2750MHz (DDR4-5500) on MSI X299 LGA2066 motherboard and Intel Core i7-7740K CPU, it is still a great feat, especially considering that AMD is still working on further optimizing the memory performance on AM4 platform.