How to Fix Slow Internet Speed on Your Computer

Published 2026-10-16 · LuxuriousComputers Repair

When the internet is slow on your computer but works fine on your phone or other devices, the problem is with the computer, not your internet service. When it is slow on every device, the problem is your network or ISP. This guide covers both scenarios, starting with the computer-specific fixes that solve most cases.

Quick checks that fix most slow internet

Restart everything

Power cycle in this order: turn off the computer, unplug the modem for 30 seconds, unplug the router for 30 seconds, plug the modem back in, wait for all lights to stabilize, plug the router back in, wait for it to fully boot, then turn on the computer. This clears stale routing tables, DHCP leases, and DNS caches across all devices and resolves a surprising number of speed problems.

Run a speed test from the right place

Before spending time on fixes, measure the problem. Open a browser and run a speed test at a site like speedtest.net or fast.com. Compare the result to what your ISP plan says you should get. Then run the same test on your phone connected to the same Wi-Fi network. If the phone gets full speed but the computer does not, the problem is computer-specific.

For the most accurate test, connect the computer directly to the router with an Ethernet cable and test again. If the wired speed is normal but Wi-Fi is slow, the problem is the wireless connection, not the internet itself.

DNS server optimization

Your DNS server translates website names into IP addresses. Your ISP's default DNS server is often slow or overloaded, which makes every website feel sluggish even though your raw bandwidth is fine.

Change your DNS on Windows

1. Open Settings, then Network & internet
2. Click your connection (Wi-Fi or Ethernet)
3. Click Hardware properties
4. Next to DNS server assignment, click Edit
5. Switch to Manual, enable IPv4, and enter 1.1.1.1 as Preferred and 1.0.0.1 as Alternate (these are Cloudflare's public DNS servers, among the fastest available). Google's DNS at 8.8.8.8 and 8.8.4.4 is another good option
6. Save and test. Pages that were slow to start loading should now pop up faster

Change your DNS on Mac

1. Open System Settings, then Network
2. Click your active connection, then Details
3. Click DNS in the sidebar
4. Remove existing entries and add 1.1.1.1 and 1.0.0.1
5. Click OK, then Apply

Flush the DNS cache

A corrupted DNS cache can cause slow lookups or failed connections to specific sites. Clear it:

• Windows: Open Command Prompt as administrator and run ipconfig /flushdns
• Mac: Open Terminal and run sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

Network adapter driver issues

An outdated, corrupted, or wrong network driver is one of the most common causes of slow internet that only affects one computer.

Update the driver

1. Open Device Manager on Windows
2. Expand Network adapters
3. Right-click your Wi-Fi adapter (usually says Intel, Realtek, Qualcomm, or Broadcom in the name) and choose Update driver, then Search automatically
4. If Windows finds an update, install it and restart

Reinstall the driver

If updating did not help, a clean reinstall often fixes corruption:

1. In Device Manager, right-click the Wi-Fi adapter and choose Uninstall device. Check the box to delete the driver software if offered
2. Restart the computer. Windows will reinstall a basic driver on boot
3. For the best performance, download the latest driver from your laptop manufacturer's support page (not just the chip vendor) for your exact model

Check for driver rollback

If the slow speed started after a recent Windows update, the update may have installed a newer but buggy driver. In Device Manager, right-click the adapter, choose Properties, then the Driver tab. If Roll Back Driver is available, try it.

Windows network settings that slow things down

Metered connection

If your connection is set to metered, Windows throttles background downloads and some apps may limit their bandwidth usage. Go to Settings, Network & internet, click your connection, and make sure Set as metered connection is off.

Background bandwidth usage

Windows Update, OneDrive sync, and other background processes can quietly consume your bandwidth:

• Open Task Manager (Ctrl + Shift + Esc), click the Network column to sort by bandwidth usage, and see if anything is consuming an unexpected amount
• In Settings, Windows Update, Advanced options, Delivery Optimization, you can limit the bandwidth Windows Update uses for downloads
• Pause OneDrive sync temporarily (right-click the OneDrive icon in the system tray) to see if your speed improves

TCP/IP and Winsock reset

Corrupted network stack settings can cause persistent slow speeds. Open Command Prompt as administrator and run these commands one at a time:

netsh winsock reset

netsh int ip reset

ipconfig /release

ipconfig /renew

ipconfig /flushdns

Restart the computer after running all five.

Wi-Fi specific speed problems

If your speed is slow on Wi-Fi but normal on Ethernet, the wireless connection is the bottleneck:

• Distance and walls. Wi-Fi signal degrades with distance and through walls, especially concrete, brick, and metal. Move closer to the router to test. If speed improves significantly, the issue is signal strength. A Wi-Fi extender, mesh system, or Ethernet cable to your desk solves this
• Channel congestion. In apartments and dense neighborhoods, dozens of networks compete on the same channels. Your router's admin page usually shows what channel it is on. Try switching to a less crowded channel, or enable auto-channel selection. On the 5 GHz band, channels 36, 40, 44, and 48 (UNII-1) are the least congested in most areas
• 2.4 GHz vs 5 GHz. The 2.4 GHz band has better range but lower maximum speed (usually 50 to 100 Mbps real-world). The 5 GHz band is faster (200 to 800+ Mbps) but has shorter range. If your computer is connecting to 2.4 GHz when 5 GHz is available, right-click the Wi-Fi adapter in Device Manager, go to Advanced, and set Preferred Band to 5 GHz
• Old Wi-Fi standard. If your computer only supports Wi-Fi 4 (802.11n), it cannot take advantage of a modern Wi-Fi 5 or Wi-Fi 6 router. Check your adapter's properties in Device Manager for the supported standard. A USB Wi-Fi 6 adapter is an inexpensive upgrade
• Interference. Microwaves, cordless phones, baby monitors, and Bluetooth devices all operate near 2.4 GHz and can cause interference. If your speed drops when the microwave runs, switch to 5 GHz

Browser-specific slowness

If the internet feels slow only in the browser but downloads and speed tests are fast:

• Clear the browser cache and cookies. A bloated cache can slow page rendering
• Disable browser extensions one by one. Ad blockers, VPN extensions, and privacy tools can slow page loads. Test in a private/incognito window (which disables extensions) to confirm
• Try a different browser entirely. If Chrome is slow but Firefox is fast, the problem is Chrome-specific (usually an extension or corrupted profile)
• Check if a VPN is active. VPNs route your traffic through a remote server, adding latency and often reducing speed. Disconnect the VPN and test

When the problem is your network or ISP

If every device is slow:

• Router age and capabilities. Routers older than 4 to 5 years may not support the speeds your ISP now provides. If your ISP gives you 500 Mbps but your router only supports 100 Mbps on its WAN port, you are hardware-limited. Check your router's specifications
• Too many devices. Each device on the network shares the available bandwidth. Streaming on three TVs while someone else is video calling and gaming will slow everything down. Quality of Service (QoS) settings on your router can prioritize important traffic
• ISP issues. Check your ISP's status page or outage map. Contact them if your speed is consistently well below what you pay for, especially if it is slow on a wired connection directly to the modem. They may need to check the line to your house

Internet speed help in Marion

LuxuriousComputers in Marion troubleshoots and fixes slow internet problems. Whether it is a driver issue, a Wi-Fi configuration problem, or network hardware that needs upgrading, we diagnose the cause and get your connection running at the speed you are paying for. We also set up home and small business networks, Wi-Fi extenders, and mesh systems.