ASROCK 890GX Extreme4 Manual Del Usuario página 21

Step 2. Install one Radeon graphics card to PCIE3 slot. For the proper installation
procedures, please refer to section "Expansion Slots".
Step 3. Install one Radeon graphics card to PCIE4 slot. For the proper installation
procedures, please refer to section "Expansion Slots".
Step 4. Use one CrossFire
and PCIE3 slots, and use the other CrossFire
graphics cards on PCIE3 and PCIE4 slots. (CrossFire
with the graphics card you purchase, not bundled with this motherboard.
Please refer to your graphics card vendor for details.)
CrossFire
ASRock
TM
Bridge to connect Radeon graphics cards on PCIE2
TM
TM
Bridge
890GX Extreme4 Motherboard
Bridge to connect Radeon
TM Bridge is provided
2 1 2 1 2 1
2 1 2 1