Yesterday I installed a switch between one of my cable modem/router combo ethernet ports and my personal desktop. No way of knowing for sure, but it's been working as designed for hours now with multiple restarts and shut-downs. The reason I am thinking this is because, every time I turn off the PSU and remove the cable, my GPU LEDs reset, but only when power is completely removed from the motherboard, not when the computer is simply shut off. I'm thinking that fully removing power from the motherboard and allowing any components to deenergize allowed the NIC to reset per se.

Between originally installing the switch (when this problem first occurred) and step 4 above, I never turned off my PSU (the actual switch on the PSU, not just turning the computer off) / disconnected the power cable. keep reading: Moved computer back up to original location, connected to switch using all the same cables from before today (aside from the RJ45 connecter I changed). You're probably thinking it was the cable. Temporarily relocated computer down to cable modem/router combo and connected to existing port on cable modem/router combo with different cable.

wireless network achieves internet plan speeds (250Mbps), wired network now reads 'Brett', wired network STILL limited at 100Mbps. Replaced RJ45 connector on cable from cable modem/router on end closest to computer. These are the things I did today, in order: My computer is back up and running with a 1.0 Gbps connection and identifies instantaneously.

Msi killer e2400