I have a Ryzen 5900. So mine was definitely affected. A very helpful person on reddit helped me out. I just changed the overclock profile to custom and changed it to 1700 MHZ. And just like that the RAM is up to the speed it initially was. What is utterly amazing to me is that the Alienware/Dell technical support has not the slightest idea of the problem I am describing or how to fix it. Any other place knows how to troubleshoot these PCs better than the premium support I paid for.  
The most recent 2.2.6 BIOS update on my Aurora R10 seems to have maxed my RAM speed to 2667MHz. I have installed aftermarket Crucial Ballistix 3600MHz. 2x16GB sticks. No XMP profiles in the BIOS change anything.When I swap to the original OEM stick of ram it goes automatically to 3200MHz. That is what that RAM was rated. Dell’s solution was to purchase RAM at 3400MHz instead and what I have was compatible. Before the BIOS update it was running at 3400MHz. Buying new RAM can’t possibly be the solution. Any suggestions?
Aurora R10, BIOS 2.2.6 update, ram max 2667MHz