INSTEAD, SWAP YOUR SUSPECT MOTHERBOARD INTO ANOTHER WORKING RIG!
If your public IP changes, your panel ID will change.
It is recommended to assign static IPs based on mac addresses on your router.
However, you can also set a static IP on linux itself: eth OS automatically assigns a 6-character panel ID based on a hash of your external IP address.
Please use the pool-side effective hashrate to see your true hashrate for the entire rig.
I've recently decided that I want to try and utilize my two graphics cards so that I can have a dual monitor setup.