Anonymous sources inside Asus headquarters have reportedly confirmed to VideoCardz the existence of AMD X590 and X599 motherboards.
Before AMD released the X570 chipset, there were mumblings that the chipmaker would release it in two flavors. The rumors pointed to an 11W variant for consumer motherboards and a 15W variant for high-performance motherboards. References to the X570 and X590 chipsets inside Gigabyte's BIOS files have lent credence to this rumor.
The X570 chipset is most likely the consumer offering making the X590 chipset the higher-end part. Besides the obvious difference in power draw, the X590 chipset could come with more PCIe 4.0 lanes. If we had to take a wild guess, we would bet on four more PCIe 4.0 lanes. One of the caveats with X590 that we can think of would be cooling. A higher power draw would mean a more aggressive fan curve to keep the chipset cool.
Asus' confidential documents mention the Prime X590-Pro and ROG Strix X590-E motherboards. VideoCardz noted that the motherboards are probably in the development stage and may or may not make it to the market. There's a good chance that motherboard manufacturers are preparing their X590 motherboards for the Ryzen 9 3950X launch in September.
In other news, VideoCardz also claims to have also discovered Asus's plan to release the successor to the ROG Zenith Extreme motherboard, which is based on the current X399 chipset. The ROG Zenith II Extreme, as it is allegedly called, could feature the brand new X599 chipset to house AMD's forthcoming Ryzen Threadripper 3000-series HEDT (high-end desktop) processors. Unfortunately, we still don't have a concrete launch date for the core-heavy chips except that they are slated to come out before the end of the year.