Nvidia “apologies” for the driver, and said that it was not a code for run on production; it was for development purposes. I guess that functionality will not be out again in an official driver
As I see, some expert mind on nvidia has to decode what is the difference between the current driver, 470 driver and 470 official driver, and see which is the difference, in terms of instructions. Maybe a kind of MOV or ST with some kind of magic number will unlock this. I bet my two cents that nvidia will remove that microcode on 470 official driver.
So far, for me was very difficult to find a motherboard with 2x PCIe 16x, running both at 8x. Motherboards with chipsets for LGA1200 have all the second one PCIe 16x at 4x.
I’ve found an Asus Maximus VI , with 3x PCIe x16, can run the first two at 8x. I’ve bought one of that, but are super hard to find