So , i have an ivy bridge system with Z77 intel chipset and here is what i have found about this driver install not being needed.
It installs itself when i have my intel HD4000 IGP disabled , and thus a secondary monitor attached to my Vega 64 card. PCI root complex gets renamed Pci bus and gets the amd driver added.
When the internal IGP is Enabled (secondary monitor attached to it), i can install crimson for my Vega 64 without it installing the AMD Pci bus driver...… BONKERS. yes it stays pure Microsofts PCI root complex driver.
Something for AMD to look into.
and it also seems to have fixed the memclock being stuck at max of 945 MHz from boot on since crimson 18.6.1.