ASROCK 970M Pro3 Handbuch Seite 18

2.4 Expansion Slots (PCI and PCI Express Slots)
here is 1 PCI slot and 3 PCI Express slots on the motherboard.
Before installing an expansion card, please make sure that the power supply is
switched of or the power cord is unplugged. Please read the documentation of the
expansion card and make necessary hardware settings for the card before you start
the installation.
PCI slot:
he PCI1 slot is used to install expansion cards that have 32-bit PCI interface.
PCIe slots:
PCIE1 (PCIe 2.0 x1 slot) is used for PCI Express x1 lane width cards.
PCIE2 (PCIe 2.0 x16 slot) is used for PCI Express x16 lane width graphics cards.
PCIE3 (PCIe 2.0 x16 slot) is used for PCI Express x4 lane width cards.
PCIe Slot Conigurations
Single Graphics Card
Two Graphics Cards in
CrossFireX
For a better thermal environment, please connect a chassis fan to the motherboard's
chassis fan connector (CHA_FAN1) when using multiple graphics cards.
16
TM
Mode
PCIE2 PCIE3
x16 N/A
x16 x4