Fujitsu PRIMERGY RX2520 M4 Operating Manual page 26

Functional overview
Slots
PCI-Express - Gen3 x16
PCI-Express - Gen3 x8
Slot notes
26
3 x low profile
3 x low profile
CPU1 supports three slots PCIe Gen3 x8 and
one slot PCIe Gen3 x16.
One PCIe Gen3 x8 slot can be occupied with a
Modular RAID controller.
CPU2 supports two slots PCIe Gen3 x16.
Operating Manual
RX2520 M4