Understanding and Troubleshooting Slow Internet on Certain Devices Despite Full Modem Speeds
Introduction
Experiencing sluggish internet speeds on specific devices can be frustrating, especially when your modem and overall network setup seem to be functioning correctly. If you’ve noticed that some laptops or computers are experiencing download speeds below 1Mbps while others, including phones and virtual machines, operate normally, this guide aims to help you identify and resolve the issue efficiently.
Network Setup Overview
- Internet Service: Fiber optic connection provided through an ISP modem.
- Router: TP-Link AX3000 (less than one year old).
- Devices Affected: Multiple laptops running Windows.
- Devices Unaffected: Smartphones, Linux virtual machines on Windows hosts.
Problem Description
The core issue involves certain laptops experiencing extremely slow internet speeds—measured at less than 1Mbps via fast.com—despite the modem indicating full speeds. Other devices, including phones and VMs, operate seamlessly at normal speeds.
Troubleshooting Efforts to Date
- Hardware Resets and Rebooting
- Unplugged and reconnected both the modem and router.
- Restarted affected laptops and devices.
- Firmware and Driver Updates
- Ensured the latest drivers and firmware are installed for both computers and the router.
- Connection Type Testing
- Switched affected devices from Wi-Fi to Ethernet; no speed improvement.
- Verified wired connection directly from modem to speed test provider showing no issues.
- IoT Device Management
- Temporarily disconnected all IoT devices; no impact on the problem.
- Router Configuration Reset
- Restored router settings to default, aside from login credentials.
- Quality of Service (QoS) Settings
- Disabled QoS; unsure if configured correctly.
- Cabling
- Tested with different Ethernet cables between modem and router; no difference.
Additional Observations
- Link speed from affected laptops to the router is approximately 1200 Mbps, indicating that physical link quality is stable.
- Task Manager’s network tab shows minimal network activity during slowdowns.
- The Windows host containing a Linux VM exhibits the problem, but the Linux VM itself runs fine without speed issues.
Potential Connections and Considerations
Since the modem’s speed tests are normal when connected directly, and the problems only occur on specific devices or within Windows environments, the root cause might stem from:
- Windows driver issues, particularly related to network adapters.
- Misconfigured or incompatible
Share this content:
