Fujitsu D3320 PRIMERGY BX2560 M2 Reference Manual page 21

3GB
The memory hole has a size of 3 GB. The remaining 1 GB address
space, below the 4G address boundary is available for DRAM.
Typically this selection is only used with 32-bit operating systems
and PCI adapter cards, which consume a huge amount of PCI
address space.
I
The PCI address decoding of 32-bit operating systems is limited
by the 4GB address boundary, even if the available PCI devices
would also support 64-bit address decoding.
SR-IOV Support
If the system has SR-IOV capable PCIe devices, this option enables or
disables Single Root IO Virtualization Support.
Disabled
Single Root IO Virtualization Support is inactive.
Enabled
Single Root IO Virtualization Support is active.
BX2560 M2
D3320 - BIOS Setup Utility
Advanced menu
21