MSI A55M-E45 V2 Manual page 26

PCI_E1~E3: PCIe Expansion Slots
The PCIe slot supports the PCIe interface expansion card.
PCI1: PCI Expansion Slot
The PCI slot supports the PCI interface expansion card..
Important
When adding or removing expansion cards, always turn off the power supply and
unplug the power supply power cable from the power outlet. Read the expansion
card's documentation to check for any necessary additional hardware or software
changes.
PCIe 3.0 x16 Slot
PCIe 2.0 x16 Slot
PCIe x1 Slot
PCI Slot
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