Ongoing Slow Internet on 2Gbps Plan Despite Troubleshooting Steps

Hi, I need some serious help here because I’ve tried just about everything and my connection is still nowhere near what I’m paying for.

I’m on the Xfinity 2Gbps plan using an XB8 gateway and a Realtek 2.5GbE Ethernet adapter. My wired speeds should be close to 2000 Mbps, but I’m barely getting 300–400 Mbps on average. Sometimes it drops even lower.

Here’s what I’ve done so far:

1. Upgraded from a Cat5e cable to a Cat6a Ethernet cable

2. Confirmed my PC supports 2.5Gbps and updated all network drivers

3. Restarted and factory reset the XB8 gateway

4. Checked aggregated link speed — it shows 2500/2500 Mbps, so the gateway seems fine

5. Verified my plan and data cap through the Xfinity app

6. Ran multiple speed tests at different times of day, both wired and wireless

7. Ruled out my PC as the issue — Micro Center diagnostics say everything is fine

8. Tried changing adapter settings but there’s no visible port configuration option

9. Tested different Ethernet ports on the gateway

10. Power-cycled everything multiple times

Other details:

• I’m only testing on a single device, no heavy uploads or downloads running

• This happens even when directly connected to the XB8

• My Realtek NIC shows a stable 2.5Gbps link

• I’ve confirmed the area doesn’t have any known outages

At this point, I’m wondering if:

• My XB8 could be throttled or defective

• There’s provisioning issues on Xfinity’s end

• Something needs to be configured in my account backend

• Or if there’s any known compatibility issues with 2Gbps plans and Realtek NICs

I’d appreciate any help, especially from someone who can look deeper into my account or network settings on your end. I’ve spent hours troubleshooting and just need stable speeds that match what I’m paying for.

Thanks in advance.