What is "intel 945g pci express root port 2771"?

Question

I find that entry in the memory allocation list of my computer (Workstation -> Device Manager -> View -> Resource by Type). It takes up 256MB of RAM and I'm wondering what's it good for.

Answer 1

From this Intel document

Root Port: A PCI Express Port, on a Root Complex, that maps a portion of the PCI Express interconnect Hierarchy through an associated virtual PCI-PCI Bridge.

Root Complex: An entity that includes a Host Bridge and one or more Root Ports.

Yeah, some circular definitions going on here.