What to check when only one laptop has slow uploads

When one laptop uploads slowly but another works normally, it is easy to blame the internet plan. Often the difference is closer to the laptop: its Wi-Fi connection, a VPN, an app syncing files, or a network setting.

Compare both computers under the same conditions before changing anything. TooLab’s Speed Test measures upload speed along with download speed, ping, and jitter. Speed tests exchange test data with our server to measure the connection, so pause other transfers while you run one.

Compare the two laptops fairly

1. On the laptop with slow uploads, open the Speed Test. Connect to your usual network, stop active downloads or uploads, and run a test.
2. Run the same test on the other laptop. Place it near the first one and connect it to the same Wi-Fi network, not a guest network or phone hotspot. Test the laptops one after the other so they do not compete for bandwidth.
3. Repeat each test two more times over a few minutes. Note the upload result, plus ping and jitter. A single result can be affected by a brief network slowdown or test-server variation.
4. If possible, connect the slow laptop to the router with Ethernet and test again. If you do not have Ethernet, move it close to the router and repeat the Wi-Fi test.

Keep the laptops in the same place for the Wi-Fi comparison. If one is across the room or behind a wall, the test compares location as well as hardware. For the cleanest comparison, close apps that sync files, back up photos, or send large attachments on both computers.

What the results mean

Only one laptop is slow on Wi-Fi and Ethernet

The internet connection is less likely to be the main cause. Look for a VPN, background upload, security app, or network adapter problem on that laptop. If its upload remains low after those checks, try the laptop on another network to see whether the problem follows it.

Only one laptop is slow on Wi-Fi, but Ethernet is normal

The issue is probably in that laptop’s wireless connection, its Wi-Fi adapter, or how it connects to the router. A weak or busy wireless link can reduce upload speed even when the other laptop is nearby. Compare again close to the router, then check for a driver update or a different Wi-Fi network band if your router offers one.

Both laptops are slow at the same time

This points more toward the router, internet service, or another device using the connection. Pause other uploads and repeat the tests. If both remain slow, test again later or contact your internet provider with the results.

The slow laptop’s results jump around

Inconsistent results can come from Wi-Fi interference, network congestion, a VPN connection, or background traffic that starts and stops. Compare several runs rather than treating the lowest result as typical. If ping or jitter also rises during a slow upload, the connection may be busy or unstable, not simply limited to a low upload rate.

How to fix the slow laptop

1. Pause apps that send files. Check cloud storage, photo backup, file-sharing, and email apps, then pause syncing or wait for an upload to finish. A single background backup can use much of the available upload speed.
2. Check whether a VPN is involved. If it is safe and allowed, disconnect the VPN briefly and repeat the test. On Windows 11, check Settings › Network & internet › VPN. On a Mac, check System Settings › Network › VPN. Do not turn off a work or school VPN if your organization requires it.
3. Compare the Wi-Fi connection. Move the laptop near the router and test again. On Windows 11, open Settings › Network & internet › Wi-Fi and confirm it is connected to the intended network. On a Mac, open System Settings › Network › Wi-Fi. If your router has separate network names for different bands, test the same band on both laptops.
4. Reconnect to Wi-Fi. Turn Wi-Fi off and back on, then reconnect to your network. If the laptop has trouble only with this network, remove that saved network and join it again with the password. Avoid resetting the router until you have checked whether other devices are affected too.
5. Restart the laptop. A restart can clear a stuck network connection or release an app that is holding up transfers. After it starts, run the test before reopening sync and backup apps.
6. Update the wireless adapter software. On Windows 11, check Settings › Windows Update for available updates, including optional driver updates. On a Mac, check System Settings › General › Software Update. If the laptop still uploads slowly on multiple networks, check the computer maker’s support instructions for its Wi-Fi driver or service options.

When the laptop may have a hardware problem

Hardware becomes more likely if upload speed stays poor on different Wi-Fi networks, the laptop also struggles on Ethernet, and the same network works normally on other devices. A loose or damaged Ethernet port, a failing wireless adapter, or a damaged antenna can affect one laptop. If the wireless connection also drops often or becomes much worse when you move the laptop, ask the manufacturer or a repair shop to inspect it. A USB Wi-Fi adapter can help confirm whether the built-in wireless hardware is the issue, but it does not repair it.

Why one speed test is not enough

A browser speed test measures the connection between your device and a test server at that moment. It does not measure only the internet plan, and results can differ with Wi-Fi conditions, other network traffic, VPN routing, and server load. Compare repeated runs on the same network, and use a wired test when you can. If the slow result follows one laptop across more than one network, that is useful evidence to share with its support team.