I have a Desktop PC (Core i5 processor, GA-B85M-D3H Gigabyte motherboard). I want to expand the system to support 4 ethernet ports. (1 incoming, 3 outgoing ports connected to 3 different ISPs for load balancing).

How do I find out how many ethernet ports can my motherboard support? Official specifications do not talk about it.


There is no specific limit.

On a modern motherboard you have PCI-e slots and optionally a few build in Ethernet ports.

In each PCI-e slot you can add an expansion cards. That can be a traditional cheap NIC with one port, or more server orientated cards. Many of these feature 4 ports.

Thus, without doing anything exotic:

  • Count the number of ports already on the motherboard.
  • Count the number of free PCI-e slots.
  • Calculate first + 4x second.

As to exotic: The can use PCI-e to multiple PCI-2 bridges.

Example of a regular 4 ports NIC:

Thus far the generic answer. Now for your specific setup:

Your board has one on board NIC, three PCI-e conectors and two ancient PCI-connectors. In theory you could have up to 21 Ethernet ports.

That is assuming no other cards are in use, and using PCI rather than PCI-e is not recommended (it is a shared bus with relative low bandwith, you you can put a quad card in it, but a single 1Gbit NIC can saturate a 33Mhz/32bit PCI bus).

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.