I'm already trying to get this setup to work the whole day but nothing helps:
Windows 10 x64 EDU
2x Sapphire R9 390x
Asus x99-S Motherboard
Intel 5280K CPU
Powered by a EVGA 1200 P2 PSU.
the Crossfire option is not showing up for activation in CCC.
In the hardware tab i can see both card with one of them being disabled, the specs of both cards are 100% identical in CCC.
The cards are set up according to the MB manual with the crossfire/sli switch set to Two-Way residing in PCIE Slot 16x_1 and 16x_4 just as indicated by the guiding LEDs on the Motherboard.
BIOS readout confirms the first card as 16x 3.0 and the second card as 8x 3.0 just as shown in the manual.
I already tried the following things:
Installing the newest driver, using ddu to clean old installation beforehand.
Installing drivers with one card installed, installing the second one afterwords.
Installing drivers with both cards installed
Installing/booting up the system with UEFI on the graphic cards disabled/enabled.
After this i disabled automatic driver installation in windows and done the driver dance again.
Tried to set the second card in slot 3 instead of 4 and tried the above solutions this way, changed it back afterwords.
Creating a clean install of Windows 10.
Tried to install older drivers.
Tried to install beta drivers, didn't work out as the graphics card was not recognized by the driver.
Both cards work independently of each other and switching the display cable to the other card works with the first card being disabled in the process.
The second card show as disabled in CCC but Device Manager shows both of them enabled.
Please i would be grateful for any tip, dunno what to do right now.
EDIT: I'm installing Windows 7 on my secondary drive, >IF< this works out I'll have to wait until there are some actual working drivers for 10, also wait and see if dx12 is actually worth the trouble in the first place.