Could a faulty on-board NIC cause network throttle?

[dwoods99]

I am trying to determine if an unRaid server with an older motherboard is having problems with the NIC card on-board. I used to have another PC next to it but noticed that I could not have both connected to the network without extremely slow transfers, or dropped connections. Since then I've got another server which is also having problems when connected at the same time as the first server.

 

I really notice the problem when streaming music files to listen to from the first server. The music either dies off, loses connection, or the second server can't access internet.  I've tried different CAT5/6 cables and different ports on the network and switches.  Music streaming is fine if only first server is connected.

 

I suspect it's the first server NIC card going crazy causing others to fail, but not the Windows PCs in the house.

So before I go out and buy a NIC card to test it out, is there anything else to test out first to pinpoint the real problem of dropped connections?

 

EDIT:

The problem ended up being the /boot/config/network.cfg file contained HWADDR= to the NIC's MAC address and this network.cfg file was copied to another server without changing the HWADDR for the new server's MAC address.

Two servers with the same MAC address setting caused unreliable network traffic.