
My initial thought here is that the communication between your router/switch and the Killer E2400 NIC port is having issues with initial auto-negotiation. You can read more about Auto-negotiation here: Auto negotiation works in conjunction with your router or switch to try the highest link rate possible, and then working its way down. The Killer E2400 comes in many motherboards and laptops, and goes through full Microsoft Certification, which requires proper 1Gbps link-rate in WHQL testing.Ĭonsidering that disabling/re-enabling the cards causes proper link rate negotiation, I would assume that unplugging and re-plugging in the Ethernet cable would also fix the issue.

This sounds to be an Ethernet Auto-Negotiation issue upon bootup of your system.
