Your laptop crawls through a webpage while your phone streams video without skipping a beat — same router, same room, completely different experience. When only one device has slow Wi-Fi, the culprit almost never lives inside your router.
Device-level speed problems usually trace back to a handful of causes: a stale DNS cache, an outdated network driver, background apps hogging bandwidth, or the device locking onto the wrong Wi-Fi band. These six fixes address each of them in order of effort, starting with the fastest.
Quick Answer
Run a speed test at Speedtest.net on the slow device and a working device at the same time. If only one device is slow, focus on that device: forget and rejoin the Wi-Fi network, flush the DNS cache, update the network adapter driver, and close any apps downloading in the background.
Fix 1: Confirm the Gap with a Speed Test
Before changing anything, verify that the slowdown is real and device-specific.
- Close all apps and browser tabs on the slow device.
- Run a speed test on both devices simultaneously from the same room.
- Compare the results. A 20–30% difference between devices is normal; a gap of 70% or more confirms a device-level issue.
This single step rules out a router problem and tells you exactly how large the fix needs to be.
Pro tip: If your router broadcasts separate 2.4 GHz and 5 GHz networks, test the slow device on both. Devices sometimes lock onto the slower 2.4 GHz band even when a faster 5 GHz signal is within range.
Fix 2: Forget and Rejoin the Wi-Fi Network
A corrupted saved network profile or a stale IP lease can throttle a single device without affecting any other.
- Windows 11: Settings → Network & Internet → Wi-Fi → click your network name → Forget.
- iPhone: Settings → Wi-Fi → tap the (i) next to the network → Forget This Network.
- Android: Settings → Network & Internet → Wi-Fi → long-press the network → Forget.
- Reconnect as if for the first time, then rerun the speed test.
This fix takes under two minutes and resolves a surprisingly high number of single-device slowdowns.
Fix 3: Flush the DNS Cache
Every device keeps a local DNS cache. When it grows stale or corrupted, page loads slow down even when raw download speed looks fine — every website request waits longer for the initial DNS lookup to complete.
Windows
- Press Windows + R, type
cmd, then press Ctrl + Shift + Enter to open an elevated Command Prompt. - Type
ipconfig /flushdnsand press Enter. You should see “Successfully flushed the DNS Resolver Cache.”
macOS
- Open Terminal.
- Run:
sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
Android and iPhone
Toggle Airplane Mode on for 10 seconds, then off. This clears the device DNS cache without any extra steps.
Fix 4: Update or Reinstall the Network Adapter Driver (Windows)
An outdated or corrupt wireless driver is among the most common causes of a single Windows device running slow while everything else on the same network is fine.
- Right-click the Start button and select Device Manager.
- Expand Network Adapters, right-click your Wi-Fi adapter, and choose Update driver → Search automatically for drivers.
- If Windows finds nothing new, visit your laptop manufacturer’s support page and download the latest driver manually.
- Restart the PC and retest.
If updating doesn’t help, right-click the adapter and choose Uninstall device, then restart — Windows reinstalls a clean copy automatically and often fixes what an update missed.
Fix 5: Find and Stop Background Bandwidth Hogs
A single app running a large download or cloud sync in the background can consume most of your available bandwidth, leaving very little for everything else.
Windows
- Press Ctrl + Shift + Esc to open Task Manager.
- Click Performance → Open Resource Monitor → Network tab.
- Look for any process sending or receiving heavy data. Common culprits: OneDrive, Windows Update, Google Drive, and game launchers mid-patch.
Mac
- Open Activity Monitor (Cmd + Space, type “Activity Monitor”).
- Click the Network tab and sort by Rcvd Bytes or Sent Bytes.
Troubleshooting tip: Search the name of any unfamiliar process before ending it — some legitimate Windows services look suspicious at a glance.
Fix 6: Switch Wi-Fi Bands or Go Wired
Most modern routers broadcast on two or three bands simultaneously. If the slow device connects to 2.4 GHz while everything else uses 5 GHz, you’ll see a major speed gap even though the router itself is perfectly healthy.
| Band | Range | Max Speed | Best For |
|---|---|---|---|
| 2.4 GHz | ~45 m (150 ft) | ~300 Mbps | Range, older devices |
| 5 GHz | ~12 m (40 ft) | ~1.3 Gbps | Speed when near the router |
| 6 GHz (Wi-Fi 6E) | ~9 m (30 ft) | ~2.4 Gbps | High-bandwidth tasks nearby |
| Ethernet | N/A | 1–10 Gbps | Maximum speed and reliability |
In your Wi-Fi settings, look for a network name ending in “5G” and switch to it. If both bands share the same name, log into your router’s admin panel to split them or enable band steering. For the fastest and most reliable option, a wired Ethernet connection eliminates the Wi-Fi variable entirely — see our guide on fixing Ethernet issues if you run into trouble going wired.
Common Mistakes to Avoid
- Restarting the router first. If every other device is fast, the router is not the problem. Restarting it wastes time without addressing the device-specific cause.
- Ignoring the Wi-Fi band. Many users never notice their device is stuck on 2.4 GHz. Check the band early — it takes 30 seconds and fixes the issue more often than you’d expect.
- Skipping the speed test. Slow-feeling browsing can come from a slow website or server, not your connection. A speed test confirms the problem is real before you start changing settings.
- Relying on Windows Update for drivers. Windows Update frequently misses manufacturer-specific Wi-Fi driver updates. Check your laptop maker’s support site directly.
- Forgetting cloud sync apps. OneDrive, iCloud, and Google Drive silently throttle everything else when syncing large files. Always check them first under Resource Monitor.
Frequently Asked Questions
Why is my laptop slow on Wi-Fi but my phone is fast?
Laptops and phones use different Wi-Fi chips and drivers. The laptop may be on the slower 2.4 GHz band, have a corrupted network driver, or have a background app consuming bandwidth — none of which affect the phone.
Does having many devices on Wi-Fi make one device slow?
Rarely. Congestion can reduce speeds slightly for all devices, but if only one device is dramatically slower, the problem is almost always on that device rather than the number of connected devices.
Will a VPN slow down Wi-Fi on just one device?
Yes. A VPN encrypts all traffic on the device it is installed on, adding latency and reducing throughput. Disable it temporarily and retest to see if it is the cause.
Can malware cause slow Wi-Fi on only one device?
Yes — malware often runs background network activity that consumes bandwidth. If the fixes above don’t help, run a full scan with Windows Security or Malwarebytes Free.
How do I know if my Wi-Fi adapter is failing?
Signs include frequent disconnects, speeds that only recover after a reboot, and speeds that drop sharply even when close to the router. Reinstall the driver first; replacing the adapter is the last resort.
Conclusion
When only one device has slow Wi-Fi, the fix is almost always on the device itself. Start with a speed test to confirm the gap, then work through flushing the DNS cache, updating the driver, switching to 5 GHz, and closing background bandwidth hogs — most users resolve it within 15 minutes.
For problems affecting all devices, see our guides on slow internet fixes that work on any device, Wi-Fi connected but no internet, and Wi-Fi that keeps dropping.