After upgrading to a gigabit plan, my speed tests still top out around 300 Mbps. The modem/router is on a bookshelf beside the TV, and I also tested my laptop with a short Ethernet cable instead of Wi-Fi.
For people who had this issue, do you actually use the provider’s modem/router combo, put it in what I think is called bridge mode with your own router, or connect directly by Ethernet? Which setup fixed the bottleneck for you, and why?
A gigabit plan usually tests around 900 Mbps over wired Ethernet, not the full 1,000. Before buying a router, confirm the laptop’s link speed says 1.0 Gbps, use Cat5e or better, disable any VPN, and run an Ookla internet speed test directly from the provider gateway. If that still caps near 300 Mbps, bridge mode will only help if the combo unit is the bottleneck; otherwise it’s likely bad provisioning or a modem/port that cannot handle the plan. The bookshelf beside the TV can hurt Wi-Fi, but it should not explain a wired 300 Mbps result.
Was that Ethernet cable plugged into a built-in gigabit port or a USB adapter? Many USB 2.0 Ethernet dongles top out around 300 Mbps in practice, so test with a known gigabit-capable adapter before blaming the gateway or ISP.
Check what link speed your laptop reports while the cable is connected. If it says 100 Mbps, the cable or port is the problem. If it says 1.0 Gbps, then @redstream’s USB adapter concern is less likely and you can look farther upstream.
Run Speedtest by Ookla with Wi-Fi disabled, try a couple of nearby servers, and make sure no other devices are downloading. A clean gigabit Ethernet test should usually land somewhere around 850 to 950 Mbps, not exactly 1,000. If several wired tests stay near 300 Mbps, check whether the gateway has QoS or bandwidth limits enabled, then ask the ISP to confirm the modem is provisioned for the new tier. The bookshelf and TV placement may hurt Wi-Fi, but it would not explain a properly connected wired test hitting the same ceiling.
The annoying downside of plan upgrades is that the billing change can go through before the gateway receives the new speed profile. A normal reboot may pull the updated configuration, so unplug the gateway’s power for a few minutes and let it come fully back online. I would not factory-reset it yet, since that can wipe custom settings without fixing provisioning.
See whether the gateway’s app or admin page has its own speed test. That test runs between the gateway and the ISP, bypassing your laptop, cable, Wi-Fi, and the USB adapter issue @binary_optic_wizard mentioned. If the gateway itself gets roughly 900 Mbps but the laptop stays around 300, the problem is on your side of the Ethernet port. Antivirus traffic scanning, an older dock, USB limitations, or the laptop struggling with a browser-based test can all cause that.
If the gateway’s internal test is stuck near 300 too, call the ISP and ask them to verify the exact boot file or service profile assigned to the modem, not merely whether your account says “gigabit.” Give them the modem model and MAC address while you are at it. They should confirm that model is approved for the tier and send a fresh provisioning signal.
The TV and bookshelf still deserve attention later for Wi-Fi coverage, but I would leave furniture rearranging and router shopping until the gateway-side result is known. That single test should tell you which half of the connection is actually wasting your time.
The bookshelf location is not the wired problem, but the cabling behind the TV still could be. If this is cable internet, trace the coax feeding the gateway. A worn connector, an old two-way splitter, or a TV amplifier that was never meant to pass modem frequencies cleanly can leave the modem online while hurting actual throughput.
I would temporarily connect the gateway to the incoming coax with as little between them as possible. Remove any unnecessary splitter, hand-tighten the connectors, reboot the gateway, and test again. Take a photo before changing anything so you can restore the original layout. Do not remove a provider-installed filter or start replacing parts blindly.
The gateway’s built-in test is useful, but a 300 Mbps result there does not prove provisioning is the only possible cause. It only shows the slowdown is upstream of your laptop. Bad coax signal, excessive corrected errors, or a struggling fiber ONT can produce the same general symptom.
If the direct-line test stays near 300, ask support to check the WAN signal and error history in addition to the speed profile. Mention that Ethernet negotiated at 1 Gbps and that the gateway-level test is slow. That usually gets you past the basic “move closer to Wi-Fi” script and toward either a reprovision or a line technician.
A DOCSIS 3.0 modem often tops out right around 300 to 400 Mbps, while a 3.1 unit will actually pull the full gig. That oddly specific 300 ceiling makes me think the combo unit itself is too old for the tier, not the cable or the port. Check the modem model against what your ISP lists as gig-approved before chasing splitters.
Don’t let support dismiss this as “your laptop can’t do gigabit” after one test. Run wired tests on two devices at the same time and add the results. If both pull roughly 300 Mbps each, or the combined total climbs toward 900, your connection is fine and the original laptop is the choke point. If the combined total still sticks near 300, the limit is at the gateway, modem, line, or ISP profile.
I’d push back slightly on @primedrone’s claim that DOCSIS 3.0 automatically means a 300 to 400 Mbps ceiling. The exact model, channel capacity, and ISP certification matter more than the DOCSIS label alone. Check the provider’s approved-device list, but don’t buy new hardware just because the modem says 3.0.
If the gateway’s internal test and the combined-device test both cap at the same speed, stop troubleshooting furniture and laptop settings. Give the ISP those results and insist they verify the assigned speed profile and equipment compatibility. A repeatable 300 Mbps ceiling on multiple devices is useful evidence, not a Wi-Fi placement problem.