Wi-Fi Slow on One Device But Fast on Others? (2026 Fix Guide)

When your Wi-Fi is slow on only one device but fast on others, the problem is almost always isolated to that specific device, not your router or ISP. The most common causes are outdated Wi-Fi drivers, the device being stuck on the slower 2.4 GHz band, Windows power management throttling the wireless adapter, DNS cache corruption, or background processes consuming bandwidth. The good news is that nearly every cause has a free fix you can apply in under 10 minutes.

I have spent years helping friends, family, and forum users diagnose exactly this problem. The pattern is always the same: one laptop crawls at 2 Mbps while a phone in the same room pulls 200 Mbps on the same network. People blame the router, call their ISP, even buy new equipment, only to find the issue was a single setting on the slow device.

This guide walks you through every possible cause, starting with the fastest diagnostic tests and working toward deeper fixes. By the end, you will know exactly why is my wifi slow only on one device but fast on others and how to fix it permanently. No guesswork, no wasted money on unnecessary upgrades.

Here is what we will cover: a 2-minute quick diagnosis to confirm the problem is device-specific, seven numbered troubleshooting steps from easiest to most involved, device-specific fixes for Windows, Mac, iPhone, Android, and Smart TV, a hardware limitations section with a Wi-Fi standard comparison table, and answers to the most common questions from Reddit and support forums.

Quick Diagnosis: Narrow Down the Cause in 2 Minutes

Before changing any settings, confirm the problem is truly device-specific. This 2-minute test saves you from wasting hours troubleshooting your router when the issue lives inside one laptop or phone.

Go to speedtest.net on the slow device and run a test. Immediately walk to the same room and run the same test on a device that works normally. Write down both results. If the working device gets 150 Mbps and the slow device gets 5 Mbps, you have confirmed a device-specific problem.

Here is a quick decision table to help you interpret your results:

If both devices are slow: The problem is your router, modem, or ISP connection, not one device. Check for router firmware updates, restart your modem, or contact your ISP.

If only one device is slow: The problem is inside that device. Continue to Step 1 below to narrow it down further.

If the slow device is also slow on other Wi-Fi networks: This confirms the problem follows the device. You can rule out your router entirely and focus on device-side fixes like drivers, power management, and background processes.

If the slow device works fine on other networks but not yours: This points to a router-side interaction with that specific device. Check for IP address conflicts, DHCP lease issues, or router firmware updates that address compatibility with your device’s Wi-Fi adapter.

One important note on what counts as “slow.” A 20-30% difference between devices is normal due to different Wi-Fi adapters and antennas. You are looking for a dramatic gap, like one device at 100+ Mbps and another at under 20 Mbps, or one device loading pages instantly while another times out.

Step 1: The Definitive Ethernet Cable Test

This is the single most important diagnostic step. Connect the slow device directly to your router using an Ethernet cable, then run another speed test. The result tells you everything you need to know about where the bottleneck lives.

If the Ethernet speed test comes back fast (matching your other devices), the problem is specifically your Wi-Fi adapter or its configuration. Your device’s network stack, DNS, and software are all working correctly. The issue is purely wireless, which narrows your troubleshooting to Wi-Fi drivers, Wi-Fi band, power management, and signal strength.

If the Ethernet speed test is also slow, the problem is deeper than Wi-Fi. This points to background processes consuming bandwidth, DNS corruption, malware, VPN or proxy interference, or a failing network adapter. You should skip ahead to Steps 5, 6, and 7.

For laptops without an Ethernet port, a USB-to-Ethernet adapter works perfectly for this test. You do not need an expensive one. Any basic adapter that supports gigabit speeds will give you an accurate reading.

Forum users on Tom’s Guide and Reddit consistently report that this test is the most trusted diagnostic method. One user shared that their ASUS Vivobook was getting 0.2 Mbps on Wi-Fi but full speed on Ethernet, which confirmed the Wi-Fi adapter was the problem, not the router. Another user discovered their laptop was equally slow on both Wi-Fi and Ethernet, which pointed to a startup program hogging bandwidth.

Write down your Ethernet speed test result. You will use it as a reference point throughout the rest of this guide.

Step 2: Check Your Wi-Fi Band (2.4 GHz vs 5 GHz)

This is the single most common cause of one device being slow on Wi-Fi while others are fast. Most modern routers broadcast two frequency bands: 2.4 GHz and 5 GHz. The 2.4 GHz band travels farther but tops out around 50-70 Mbps in real-world conditions. The 5 GHz band has shorter range but delivers speeds of 300 Mbps to over 1,000 Mbps.

When a device connects to the wrong band, the speed difference is dramatic. A phone on 5 GHz might get 350 Mbps while a laptop stuck on 2.4 GHz crawls at 25 Mbps, even though both are connected to the same router in the same room.

Here is why this happens. Many routers use “band steering,” which automatically assigns devices to a band. The router’s algorithm is not perfect. It sometimes pushes a device to 2.4 GHz because the signal appears stronger, even though the speed is much slower. Band steering behavior varies by router brand: ASUS routers tend to be aggressive about moving devices to 5 GHz, Netgear’s Smart Connect can be inconsistent, and Eero and Google Nest use mesh-specific steering that sometimes keeps devices on 2.4 GHz for stability.

To check which band your slow device is on:

On Windows: Click the Wi-Fi icon in the taskbar. Hover over your connected network. A tooltip will show the frequency band. Alternatively, open Command Prompt and type netsh wlan show interfaces and look for the “Band” line.

On Mac: Hold the Option key and click the Wi-Fi icon. A dropdown menu will appear showing the channel and band (it will say “Channel: X (5 GHz)” or similar).

On iPhone: Unfortunately, iOS does not show the band directly. You can check by using the AirPort Utility app (enable Wi-Fi Scanner in settings) or by temporarily renaming your 2.4 GHz and 5 GHz networks to different names.

On Android: Settings > Network & Internet > Wi-Fi > tap your network. The frequency is usually listed under “Frequency.”

If your device is on 2.4 GHz and your router uses a single network name (SSID) for both bands, the fix is to separate them. Log into your router’s admin panel (usually 192.168.1.1 or 192.168.0.1) and create separate SSIDs, like “MyNetwork_2.4” and “MyNetwork_5G.” Then connect the slow device to the 5 GHz network manually.

Another effective trick: tell your device to “forget” the network, then reconnect. This forces the device to renegotiate with the router and can resolve band steering issues. On phones, also try disabling and re-enabling Wi-Fi, which sometimes triggers a band switch.

If your router does not have a 5 GHz band at all (some older or budget models only broadcast 2.4 GHz), that is your answer. No device on your network will exceed about 50-70 Mbps regardless of how fast your internet plan is. Upgrading to a dual-band or tri-band router is the fix.

Step 3: Update Your Wi-Fi Drivers

Outdated or corrupted Wi-Fi drivers are the second most common cause of a single device getting slow speeds. This is especially common on Windows PCs, where Windows Update frequently installs generic Microsoft Wi-Fi drivers that replace the manufacturer’s optimized drivers.

Here is what happens: your laptop came with a Wi-Fi adapter made by Intel, Realtek, Qualcomm, or MediaTek. The manufacturer’s driver is tuned for that specific chip. Windows Update comes along, installs a generic driver, and suddenly your Wi-Fi speeds drop by 50-90%. This happens silently in the background, so you might not connect the dots.

To fix this on Windows, you need to get the driver directly from the manufacturer, not from Windows Update:

Step 3a: Open Device Manager (right-click the Start button and select Device Manager). Expand “Network adapters” and note the exact name of your Wi-Fi adapter (for example, “Intel Wi-Fi 6 AX201” or “Realtek 8821CE Wireless LAN 802.11ac PCI-E NIC”).

Step 3b: Download the latest driver from the manufacturer’s website. For Intel adapters, go to Intel’s download center. For Realtek, visit Realtek’s official site. For Qualcomm Atheros, check your laptop manufacturer’s support page. For MediaTek, use your laptop manufacturer’s site.

Step 3c: In Device Manager, right-click your Wi-Fi adapter and select “Update driver.” Choose “Browse my computer for drivers,” point it to the downloaded driver file, and install it. Restart your computer after installation.

Step 3d: To prevent Windows Update from replacing your driver again, download and run Microsoft’s “Show or Hide Updates” troubleshooter tool. Use it to hide the generic Wi-Fi driver update so Windows does not overwrite your manufacturer driver.

On Mac, Wi-Fi driver updates are bundled into macOS system updates. Go to System Settings > General > Software Update and install any available updates. If the problem started after a macOS update, check Apple’s support forums for known Wi-Fi regressions in that version.

On phones, driver updates come through OS updates. Check for system updates on iPhone (Settings > General > Software Update) or Android (Settings > System > System update). If a recent update caused the slowdown, check if others report the same issue on forums.

Reddit users in r/techsupport and r/HomeNetworking frequently report that driver updates alone fix the problem. One user with a Realtek 8821CE adapter went from 0.2 Mbps to full speed after installing the Realtek driver instead of the Windows generic one. Another user fixed an Intel AX200 adapter that was dropping to 5 Mbps by updating to Intel’s latest driver package.

Step 4: Disable Wi-Fi Power Management

Windows laptops have a feature called Wi-Fi power management that reduces power to the wireless adapter to extend battery life. On some devices, this feature aggressively throttles the Wi-Fi adapter, cutting speeds by 50-80%. The throttling happens automatically and silently, so the only symptom is mysteriously slow Wi-Fi on one device.

This problem is specific to Windows. Mac and mobile devices manage Wi-Fi power differently and are rarely affected by this issue.

To disable Wi-Fi power management on Windows:

Step 4a: Open Device Manager and expand “Network adapters.” Right-click your Wi-Fi adapter and select “Properties.”

Step 4b: Go to the “Power Management” tab. Uncheck “Allow the computer to turn off this device to save power.” Click OK.

Step 4c: Open Windows Settings > System > Power & battery. Click “Power mode” and set it to “Best performance” or “Balanced” (avoid “Best power efficiency” which can throttle network adapters).

Step 4d: Open Control Panel > Power Options > Change plan settings > Change advanced power settings. Expand “Wireless Adapter Settings” > “Power Saving Mode.” Set both “On battery” and “Plugged in” to “Maximum Performance.”

Step 4e: If your Wi-Fi adapter properties have an “Advanced” tab, look for settings like “Power Save Mode,” “U-APSD support,” or “Adaptive Power Management.” Set them to disabled or off. The exact settings vary by manufacturer.

The trade-off is that disabling power management reduces battery life by approximately 5-15% depending on your usage patterns. For most users, this is a worthwhile trade for restoring full Wi-Fi speeds. You can always re-enable power management when running on battery if you need maximum runtime.

Many forum users report that power management settings reset after a reboot or Windows update. If you find the setting keeps re-enabling itself, check your laptop manufacturer’s bundled software (like Lenovo Vantage, Dell Optimizer, or HP Command Center), as these programs may override your manual settings.

Step 5: Flush DNS and Reset the Network Stack

DNS cache corruption and network stack issues can cause dramatic slowdowns on a single device. Your speed test might show normal bandwidth, but web pages take forever to load because DNS resolution is slow or broken.

Symptoms of DNS or network stack problems include: pages loading slowly or timing out, some websites working fine while others do not load at all, speed test results that look normal but real-world browsing is painfully slow, and intermittent connectivity drops.

Here are the exact commands to fix these issues on Windows. Open Command Prompt as Administrator (search “cmd” in the Start menu, right-click, and select “Run as administrator”):

Flush DNS cache: Type ipconfig /flushdns and press Enter. You should see “Successfully flushed the DNS Resolver Cache.”

Release and renew IP address: Type ipconfig /release then ipconfig /renew. This forces your device to request a fresh IP address from the router’s DHCP server.

Reset Winsock: Type netsh winsock reset and press Enter. This resets the Windows Sockets API to its default state, which can fix corruption caused by VPN software, malware, or failed driver installations.

Reset TCP/IP stack: Type netsh int ip reset and press Enter. This rewrites the TCP/IP registry keys to their installation defaults. This is the most aggressive network reset, but it is also the most effective for stubborn issues.

Reset firewall and security to defaults: Type netsh advfirewall reset and press Enter. This restores Windows Firewall to its default settings in case a misconfigured rule was blocking traffic.

After running all these commands, restart your computer. The restart is mandatory, as the network reset changes do not take full effect until the system reboots.

What to expect after the reset: your Wi-Fi will reconnect automatically, but you may need to re-enter your Wi-Fi password. Any custom DNS settings (like Google DNS or Cloudflare DNS) will be reset to automatic, so you will need to reconfigure those if you use them. VPN software may need to be reconfigured or reinstalled.

On Mac, the equivalent reset is to go to System Settings > Network > Wi-Fi > Details and click “Renew DHCP Lease.” For a deeper reset, delete the Wi-Fi service entirely and re-add it. You can also flush DNS on Mac by opening Terminal and running sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder.

On iPhone, go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. This removes all saved Wi-Fi passwords and VPN configurations, so have those handy before resetting.

On Android, go to Settings > System > Reset options > Reset Wi-Fi, mobile & Bluetooth. The exact path varies by manufacturer.

Step 6: Hunt Down Background Processes Eating Your Bandwidth

Sometimes the problem is not your Wi-Fi at all. A background process on your device is quietly downloading or uploading data, consuming your bandwidth and leaving little for your actual browsing. The speed test might even look normal if the process pauses during the test, making this an especially tricky problem to diagnose.

The most common hidden bandwidth hogs include:

OneDrive, Google Drive, Dropbox, and iCloud syncing large files in the background. If you dropped a 5 GB video into your cloud folder, the sync client will upload it at maximum speed, saturating your connection for minutes or hours.

Windows Update downloading feature updates or large driver packs. Windows does not always show a notification for these downloads, and they can consume your entire bandwidth for 10-30 minutes.

Steam, Epic Games, or other game launchers auto-downloading updates or new game installations. A single game update can be 20-80 GB.

Antivirus software running full system scans that download cloud-based definitions or upload suspicious files for analysis.

Malware, particularly cryptominers or botnet software, using your connection to communicate with command-and-control servers.

Streaming services pre-buffering content or downloading episodes for offline viewing.

To identify bandwidth hogs on Windows, open Task Manager (Ctrl + Shift + Esc) and go to the “Performance” tab. Click “Wi-Fi” to see real-time network usage. Then switch to the “Processes” tab and sort by “Network” to see which apps are using your connection. The process consuming the most network is your culprit.

For a more detailed view, use Resource Monitor (search “Resource Monitor” in the Start menu). The “Network” tab shows every process with active network connections, total bytes sent and received, and which remote servers they are connecting to.

On Mac, open Activity Monitor (Applications > Utilities > Activity Monitor) and click the “Network” tab. Sort by “Sent Bytes” or “Rcvd Bytes” to find processes consuming bandwidth.

If you cannot identify the specific process, try a Windows Clean Boot. Press Win + R, type msconfig, go to the “Services” tab, check “Hide all Microsoft services,” then click “Disable all.” Restart and test your speed. If the problem is gone, re-enable services in batches until you find the one causing the slowdown. One Tom’s Guide forum user solved a months-long slow Wi-Fi problem this way, discovering a startup utility was the bandwidth hog.

You can also set your connection as “metered” in Windows to prevent automatic downloads. Go to Settings > Network & internet > Wi-Fi > your network properties > enable “Metered connection.” This stops Windows Update, app updates, and some cloud sync from running automatically.

Step 7: Check VPN, Proxy, and Browser Extensions

A VPN, proxy, or misbehaving browser extension can slow down a single device dramatically while leaving everything else on your network untouched. This is one of the most overlooked causes because people forget they have a VPN running or do not realize their browser extension is intercepting traffic.

VPNs route your traffic through an encrypted tunnel to a remote server. This adds latency and can reduce speeds by 20-80% depending on the VPN provider, server location, and encryption protocol. Corporate VPNs on work laptops are especially notorious for this. Multiple Reddit users report that their work laptop gets 30-50% lower speeds than their personal devices on the same network, simply because the corporate VPN is always on.

To test if a VPN is the cause, temporarily disconnect it and run a speed test. If speeds jump back to normal, the VPN is your problem. You can try switching to a closer server, changing the VPN protocol (WireGuard is typically faster than OpenVPN), or using split tunneling to exclude bandwidth-heavy apps from the VPN tunnel.

Proxy settings can also cause slowdowns, especially if a VPN or security app left proxy settings configured after uninstalling. On Windows, check by going to Settings > Network & internet > Proxy. Ensure “Use a proxy server” is off unless you intentionally configured one. On Mac, go to System Settings > Network > your connection > Details > Proxies and verify nothing is configured.

Browser extensions are sneakier. An ad blocker, privacy extension, or even a shopping extension can intercept and slow down web traffic on one browser. The test is simple: open an incognito or private browsing window (which disables most extensions) and load a few pages. If browsing is fast in incognito but slow in normal mode, a browser extension is the problem.

To isolate which extension is causing the issue, disable all extensions, then re-enable them one at a time, testing browsing speed after each. The extension that causes the slowdown is your culprit. Common offenders include ad blockers with aggressive filter lists, VPN browser extensions, security extensions that scan every page load, and shopping or coupon extensions that inject scripts into pages.

Device-Specific Fixes for Wi-Fi Slow on One Device

Different devices have different quirks. Here are platform-specific fixes that address the most common causes of slow Wi-Fi on each type of device.

Windows PC or Laptop

Windows has the most potential causes of slow Wi-Fi, but also the most tools to fix it. If you have worked through Steps 1-7 above, you have covered the main fixes. Additional Windows-specific steps include checking TCP autotuning (open Command Prompt as admin and run netsh int tcp show global; if TCP autotuning is disabled, enable it with netsh int tcp set global autotuninglevel=normal), running the Windows Network Troubleshooter (Settings > Network & internet > Advanced network settings > Network troubleshooter), and checking for IP address conflicts by running ipconfig /all and verifying your IP address does not match another device on the network.

If your PC worked fine until a recent Windows Update, you can uninstall the update. Go to Settings > Windows Update > Update history > Uninstall updates. Find the most recent update and uninstall it, then restart. If that fixes the Wi-Fi, you can pause updates temporarily while Microsoft releases a fix.

Mac (MacBook, iMac, Mac mini)

Mac Wi-Fi issues are often caused by macOS updates changing power management or Wi-Fi configuration. Start by removing all saved Wi-Fi networks (System Settings > Network > Wi-Fi > delete each network) and reconnecting fresh. If that does not work, delete the Wi-Fi interface entirely and re-add it. Create a new Wi-Fi location in Network settings and configure it from scratch, which bypasses any corrupted preferences.

Run the built-in Wireless Diagnostics tool by holding Option and clicking the Wi-Fi icon, then selecting “Open Wireless Diagnostics.” This tool scans for common issues and generates a report that can identify problems with channel selection, signal-to-noise ratio, and configuration errors.

If Wi-Fi is slow on your MacBook but your iPhone is fast on the same network, check whether the MacBook has a hardware limitation. Some older MacBooks (2014-2017 models) have Wi-Fi adapters limited to 802.11ac Wave 1, which tops out around 400 Mbps. Your iPhone likely has a newer adapter capable of faster speeds.

iPhone or Android Phone

On iPhone, the most common cause of slow Wi-Fi is Wi-Fi Assist, a feature that switches between Wi-Fi and cellular data based on signal strength. If your Wi-Fi signal is weak, Wi-Fi Assist may be routing traffic through your cellular connection without you realizing it. Go to Settings > Cellular and scroll to the bottom to disable Wi-Fi Assist if you suspect this is happening.

Another iPhone-specific issue: the “Private Wi-Fi Address” feature can cause compatibility issues with some routers. Go to Settings > Wi-Fi, tap the “i” next to your network, and toggle “Private Wi-Fi Address” off to test if it improves speeds.

On Android, check for “Smart Network Switch” or “Switch to mobile data automatically” in Wi-Fi settings. This feature behaves like iPhone’s Wi-Fi Assist and can cause apparent Wi-Fi slowdowns when the phone is actually using cellular data.

For both platforms, removing metal phone cases or wallet cases can significantly improve Wi-Fi signal. Multiple Reddit users report that metal kickstand cases, magnetic wallet attachments, and PopSockets with metal mounts can block the Wi-Fi antenna, reducing signal strength by 30-50%. Try removing your case and testing speeds to see if it makes a difference.

Also try “forgetting” the network and reconnecting on both iPhone and Android. This clears cached credentials and forces a fresh connection negotiation with the router, which can resolve band steering and DHCP issues.

Smart TV or Streaming Device

Smart TVs are frequently the slowest devices on a home network. Many budget and mid-range TVs from 2018-2022 only have 2.4 GHz Wi-Fi adapters, which means they can never exceed about 50 Mbps regardless of your internet speed. Check your TV’s specifications to confirm which Wi-Fi bands it supports.

If your TV is slow but supports 5 GHz, try connecting it via Ethernet instead. Most TVs have an Ethernet port, and a wired connection eliminates all Wi-Fi variables. If Ethernet is not practical (the TV is far from the router), consider a powerline adapter or a dedicated Wi-Fi bridge that connects to the TV via Ethernet.

For streaming sticks (Roku, Fire TV, Apple TV, Chromecast), try moving the device closer to the router or eliminating sources of interference like microwaves, baby monitors, and Bluetooth speakers that operate on the 2.4 GHz band.

Gaming Consoles (PS5, Xbox, Switch)

Consoles can experience slow downloads even when speed tests look fine. The PlayStation Network and Xbox Live servers can be the bottleneck, not your Wi-Fi. Try changing your DNS to Google (8.8.8.8 and 8.8.4.4) or Cloudflare (1.1.1.1) to see if download speeds improve. On PS5, also try pausing and resuming downloads, which sometimes triggers a faster server connection.

For gaming latency (lag), the issue is often jitter and bufferbloat, not raw bandwidth. Your speed test might show 100 Mbps download with 5 ms ping, but if jitter is high, games will feel laggy. Test for bufferbloat at waveform.com/tools/bufferbloat and configure QoS on your router if results are poor.

Hardware Limitations: When Your Device Is the Bottleneck

Sometimes the problem is not software at all. Your device’s Wi-Fi adapter simply cannot handle the speeds your router and internet plan deliver. This is especially common with older laptops, budget desktops, and entry-level phones.

Here is a comparison of Wi-Fi standards and their real-world speeds so you can check what your device is capable of:

Wi-Fi 4 (802.11n): Released 2009. Max theoretical speed: 150 Mbps per stream. Real-world speed: 30-70 Mbps. Maximum 2.4 GHz and early 5 GHz support. If your device has a Wi-Fi 4 adapter, it will never be fast, no matter what router you buy.

Wi-Fi 5 (802.11ac): Released 2014. Max theoretical speed: 1,300 Mbps. Real-world speed: 200-500 Mbps. 5 GHz only for fastest speeds. Most laptops from 2015-2020 have Wi-Fi 5 adapters, which are still capable of good speeds on modern networks.

Wi-Fi 6 (802.11ax): Released 2019. Max theoretical speed: 9.6 Gbps. Real-world speed: 500-1,500 Mbps. Handles multiple devices more efficiently. Most laptops and phones from 2020 onward have Wi-Fi 6 adapters.

Wi-Fi 6E: Released 2020. Adds 6 GHz band. Real-world speed: 800-2,000 Mbps. Less interference because fewer devices use 6 GHz. Found in flagship phones and premium laptops from 2021 onward.

Wi-Fi 7 (802.11be): Released 2026. Max theoretical speed: 46 Gbps. Real-world speed: 2,000-5,000 Mbps. Available on the newest routers and a small number of devices.

If your slow device has a Wi-Fi 4 adapter and your router is Wi-Fi 6, the device is the bottleneck. No software fix will make it faster. You have three options:

Option 1: Buy a USB Wi-Fi adapter. A USB Wi-Fi 6 adapter costs roughly $20-40 and plugs into any USB port. It bypasses your internal adapter entirely. This is the cheapest and easiest fix for laptops and desktops with outdated Wi-Fi. Look for adapters with external antennas for better range, and choose a USB 3.0 model for maximum speed.

Option 2: Replace the internal M.2 Wi-Fi card. If you have a desktop with a PCIe slot or a laptop with an accessible M.2 slot, replacing the Wi-Fi card costs about $15-25. An Intel AX210 card adds Wi-Fi 6E support to most systems. This option is more permanent than a USB adapter but requires opening your device.

Option 3: Replace the device entirely. If your laptop is more than 6-7 years old and has multiple performance issues beyond Wi-Fi, it may be time for an upgrade. New laptops come with Wi-Fi 6 or Wi-Fi 6E adapters standard.

For desktop PCs with PCIe Wi-Fi cards, check that the antenna cables are properly connected. A loose antenna connection inside the case can reduce signal strength dramatically. Some desktop cards have external antenna cables that need to be screwed onto the card’s connectors, and these can come loose during transport or maintenance. One TenForums user discovered their desktop’s antenna cable was disconnected, which explained why the PCIe card performed worse than a laptop in the same room.

Could It Be Malware? Warning Signs to Watch For

Malware is not the most common cause of slow Wi-Fi on one device, but it is one you should not ignore. If you have tried all the fixes above and nothing works, malware is a real possibility, particularly if the slowdown happened suddenly with no changes to your system.

Warning signs that malware may be causing your slow Wi-Fi include: speeds that dropped suddenly overnight with no software changes, high network activity in Task Manager or Activity Monitor even when you are not doing anything, your fans running constantly and the device running hot, browser redirects or unexpected pop-up ads, and security software that has been disabled or will not update.

Cryptominers are the most common type of malware that causes network slowdowns. They use your device’s processing power to mine cryptocurrency and communicate with mining pools over the internet, consuming bandwidth. Botnet malware uses your device as part of a distributed network, sending and receiving data constantly.

To check for malware, run a full scan with Windows Defender or your installed antivirus. For a second opinion, download Malwarebytes (the free version works fine) and run a scan. If you suspect deep malware that standard scans cannot detect, boot into Safe Mode (hold Shift while clicking Restart on Windows, then navigate to Troubleshoot > Advanced options > Startup Settings > Restart and press 4 for Safe Mode) and run scans from there.

If the problem started after downloading a specific file or visiting a particular website, that is a strong indicator of malware. Run your scans immediately and consider using your browser’s “reset to default settings” option to clear any malicious extensions or configuration changes.

Frequently Asked Questions

Conclusion

When your Wi-Fi is slow on one device but fast on others, the fix almost always lives inside that device, not your router or internet plan. The top five fixes that solve this problem for most people are: checking which Wi-Fi band the device is connected to and forcing 5 GHz, updating the Wi-Fi driver from the manufacturer’s website instead of Windows Update, disabling Wi-Fi power management in Device Manager, flushing DNS and resetting the network stack, and hunting down background processes consuming bandwidth.

If none of these fixes work, run the Ethernet cable test to determine whether the problem is Wi-Fi-specific or deeper in the system. If Ethernet is also slow, focus on background processes, VPNs, browser extensions, and malware scans. If only Wi-Fi is slow and the device is more than 5 years old, consider a USB Wi-Fi adapter as a low-cost upgrade.

The most important takeaway: do not blame your router or call your ISP until you have confirmed the problem is device-specific. Understanding why is my wifi slow only on one device but fast on others starts with isolating the issue, and the steps in this guide give you everything you need to do exactly that.