This page may be useful in case your (on-board) ethernet port has stopped working and you need to purchase a new ethernet card to replace it.
Networking not working - Cannot connect to the Internet:
PCI vs PCI-e ethernet cards:
- Gigabit Ethernet: around 100MB/s.
- PCI bus: 33Mhz x 4 bytes (32 bits) = 133MB/s, shared by all PCI devices.
- PCIe :
v1.x 250 MB/s
v2.x 500 MB/s
v3.0 985 MB/s
v4.0 1969 MB/s