Why Is My Router Speed Test Slower Than My Modem?

What It Means When the Router Is Slower Than the Modem

If a speed test connected directly to the modem is faster than a test through the router, the broadband connection may be working normally. The performance loss is more likely to occur across the router, its Ethernet connection, the Wi-Fi network, or the device running the test.

A modem test should be performed with one device connected directly to the modem using Ethernet, while the router test should use the same device, server, and test method whenever possible. Differences in test conditions can create misleading results, so compare results several times rather than relying on one measurement.

Common Reasons for a Slower Router Speed Test

Wi-Fi signal interference

Nearby wireless networks, Bluetooth devices, cordless equipment, thick walls, and household appliances can interfere with Wi-Fi signals. Interference is especially common on crowded 2.4 GHz networks and can reduce download speed, upload speed, and connection stability even when the modem receives the full broadband rate.

Weak distance or poor router placement

A router placed inside a cabinet, behind large objects, near the floor, or far from the test device may deliver a weaker signal. As signal strength falls, Wi-Fi may use slower transmission modes and create higher latency, causing the router speed test to appear much slower than the modem test.

Testing on the wrong Wi-Fi band

The 2.4 GHz band generally reaches farther but may be slower and more congested. The 5 GHz band often provides higher speeds at shorter distances, while newer routers may also support 6 GHz. A device connected to a slower band can produce lower results even when the router itself supports faster performance.

Old router hardware

Older routers may not support the speed available from a modern fiber or cable broadband plan. Limited wireless standards, slower processors, fewer spatial streams, or Fast Ethernet ports can create a bottleneck between the modem and your devices.

Limited Ethernet port speed

Some routers include 10/100 Mbps Ethernet ports rather than Gigabit or faster ports. If the modem or broadband plan can deliver more than 100 Mbps, a Fast Ethernet port will limit the router connection regardless of Wi-Fi quality.

Outdated router firmware

Firmware updates can improve wireless drivers, security, compatibility, and traffic handling. An outdated firmware version may contain performance bugs or fail to work efficiently with newer devices, resulting in slower router tests or inconsistent speeds.

Router security and traffic-management features

Quality of service, parental controls, deep packet inspection, VPN services, content filtering, and advanced firewall features can use router processing power. On some models, these settings reduce maximum throughput, particularly when many rules or encrypted connections are active.

Network congestion from other devices

Streaming video, cloud backups, game downloads, video calls, and security cameras can consume available bandwidth. A router must share its connection across all active devices, so a test performed during heavy household usage may be much slower than a direct modem test.

Device limitations

The phone, laptop, or desktop used for testing may have an older Wi-Fi adapter, power-saving settings, background applications, or a slow network driver. A device limitation can make the router appear slow even when another device receives better performance from the same network.

VPN or proxy routing

A VPN or proxy adds encryption and sends traffic through an additional server. This can reduce speed and increase latency during a router test. Disable the VPN temporarily when troubleshooting, then repeat the test to determine whether it is affecting the result.

How to Identify the Source of the Speed Loss

1. Restart the modem and router, then wait until both devices show a normal connection.
2. Connect one computer directly to the modem with a suitable Ethernet cable and run several tests.
3. Connect the same computer to the router by Ethernet and repeat the tests using the same test server.
4. Run a Wi-Fi test near the router, then test again from the usual room where the slowdown occurs.
5. Compare 2.4 GHz, 5 GHz, and 6 GHz results if those bands are available.
6. Pause downloads, streaming, backups, VPNs, and other high-bandwidth activity before testing.
7. Check the negotiated Ethernet link speed in the device network settings. A link showing 100 Mbps may indicate a port, cable, or adapter limitation.

If the direct modem result is consistently fast but the router Ethernet result is significantly lower, inspect the router ports, cable, firmware, and router settings. If router Ethernet is fast but Wi-Fi is slow, focus on signal strength, channel congestion, wireless bands, and device compatibility.

Ways to Improve Router Speed

• Place the router in a central, elevated, and open location away from metal objects and enclosed cabinets.
• Use 5 GHz or 6 GHz for high-speed devices located near the router, and use 2.4 GHz where longer range is more important.
• Choose a less congested wireless channel or enable automatic channel selection if it performs reliably.
• Update the router firmware, device operating system, and wireless network drivers.
• Use Cat5e or better Ethernet cabling for Gigabit connections and confirm that both devices support the required speed.
• Disable unused VPN, traffic inspection, parental control, or bandwidth-management features while testing.
• Disconnect unused devices and schedule large backups or downloads outside peak household usage.
• Replace an outdated router if its Ethernet ports or wireless standard cannot support the broadband connection.

When to Contact the ISP or Replace the Router

Contact the ISP if the direct modem test is also consistently below the expected service range, the modem shows connection errors, or the connection drops frequently. The ISP can check signal levels, line quality, provisioning, and local network conditions.

Consider replacing the router if it has outdated ports, cannot handle the available broadband speed, overheats, regularly disconnects, or remains slow over wired Ethernet after firmware updates and configuration checks. A new router cannot increase the capacity of the ISP plan, but it can remove a bottleneck inside the home network.

Key Takeaway

When the router speed test is slower than the modem, first separate Wi-Fi performance from wired router performance. A direct modem test, a router Ethernet test, and a controlled Wi-Fi test can reveal whether the cause is interference, distance, hardware, configuration, congestion, or the device itself. Fix the specific bottleneck before changing broadband plans or assuming that the ISP connection is at fault.