Internet Slow on One Device Only: How to Fix It

Step 1: Test affected device on a wired connection

Connect the slow device directly to the router using an Ethernet cable and run a speed test. If wired speed is fast but Wi-Fi is slow, the problem is the device's Wi-Fi adapter, driver, or its distance from the router. If wired is also slow, the issue is in the device's network stack or a process consuming bandwidth.

Step 2: Restart the device

Perform a full restart — not sleep or hibernate. A restart clears temporary network state, flushes system caches, and resets driver state. Many slow-internet-on-one-device issues are resolved by a restart alone, especially if the device has been running for days without a reboot.

Step 3: Update Wi-Fi or Ethernet driver

An outdated or corrupted network driver limits throughput even when the connection appears stable. On Windows, open Device Manager > Network Adapters > right-click your network adapter > Update driver. After updating, restart the device and run a speed test again.

Step 4: Check background processes using bandwidth

On Windows, open Task Manager (Ctrl+Shift+Esc) and click the Network column to sort by bandwidth usage. On Mac, open Activity Monitor > Network tab. Look for any process consuming significant upload or download — Windows Update, antivirus updates, or cloud sync services are common culprits consuming hundreds of Mbps in the background.

Step 5: Scan for malware

Some malware uses the infected device's bandwidth continuously — for botnet activity, cryptocurrency mining, or data exfiltration. Run a full scan with Windows Defender or Malwarebytes. A device infected with bandwidth-consuming malware will show high network usage in Task Manager even when no user applications are active.

Step 6: Check if proxy or VPN is active only on this device

A proxy or VPN configured only on the slow device routes all its traffic through an additional server, adding latency and reducing throughput. Open network settings and confirm no proxy is active. Check for VPN applications that may be running in the background and connecting automatically at startup.

Step 7: Reset network settings

On Windows, open Settings > Network and Internet > Advanced network settings > Network reset. This removes and reinstalls all network adapters and resets network components to factory defaults. It resolves deep driver or stack corruption. After the reset and reboot, reconnect to Wi-Fi and run a speed test.

Frequently Asked Questions

Why is my laptop slow on internet but phone is fast?

Because phone and laptop use completely separate network stacks. When your phone gets full speed and the laptop is slow, every component shared between them — the router, modem, and ISP — is working correctly. The problem is isolated to the laptop's Wi-Fi adapter quality, driver version, a background process consuming bandwidth, or a misconfigured network setting such as a proxy or VPN.

What app could be using all my bandwidth?

The most common background bandwidth consumers are: Windows Update (can download gigabytes of updates silently), antivirus definition updates, cloud backup services (Dropbox, OneDrive, Google Drive, iCloud, Time Machine), and peer-to-peer applications left running in the background such as BitTorrent clients. Check Task Manager on Windows or Activity Monitor on Mac, sorted by Network column, to identify the exact process.

Can malware slow internet speed?

Yes. Malware that uses your device for botnet activity, spam sending, or cryptocurrency mining consumes upload and download bandwidth continuously. The device's CPU will also run high, which slows browser performance and makes the slow internet feel even more severe. Run Malwarebytes or Windows Defender full scan if Task Manager shows high network usage with no obvious legitimate application responsible.