Why background tabs affect speed test results

Your speed test looks slower when you have other tabs open, or the result changes when you switch away from the test. That can happen because tabs may be using your connection or your computer while the test is running.

Use the Speed Test to check download and upload speed, ping and jitter. A few controlled runs can help you tell whether another tab is affecting the measurement or your connection is changing for another reason.

Compare speed test results fairly

1. Open the Speed Test and run it with the test page in front. Wait for the result to finish.
2. Note the download speed, upload speed, ping and jitter. Keep the device in the same place and on the same network for the next run.
3. Open the tabs you normally use, such as a video stream or cloud storage page, and run the test again. Avoid starting a new download just for this comparison unless you want to see how it affects the connection.
4. Close or pause the activity in those tabs, return to the test page and run it once more. Compare all three readings instead of relying on one result.

The speed test exchanges test data with our server to measure your connection. Other tabs can use the same internet connection at the same time, and browser activity can also compete for your computer's resources.

What the result means

Speed drops while another tab is streaming or downloading

The other tab may be using some of your available bandwidth. A large download, cloud backup, game update or high-resolution video can leave less capacity for the test. If ping or jitter also rises, your router may be building a queue while data is moving. This is often called loaded latency, meaning the delay while the connection is busy.

Speed changes when you switch away from the test

Some browsers reduce activity in background tabs to save power and processing time. That can make the test page update less often or run its timing code less consistently. A background tab does not necessarily make your internet connection slower, but a test that is not active may be less dependable. Repeat the test with the page visible.

Results vary even after you close other tabs

Speed can change from one run to another because of Wi-Fi conditions, network congestion, other devices, or the route to the test server. Small differences are normal. A large, repeatable change is more useful than one unusually high or low reading.

Download speed stays similar, but ping or jitter rises

The connection may still move data quickly, while its response becomes less steady under load. This can affect calls, games and remote desktop sessions more than a large file download. Try a test with no active downloads, then compare it with a run while the usual activity is happening.

How to get a cleaner reading

1. Pause active downloads and streams. Stop file downloads, video streams and game updates before testing. Wait a minute for the connection to settle, then run the test again.
2. Keep the test page in front. Leave the browser window visible until the test finishes. Avoid minimizing it or switching to a demanding tab while results are being measured.
3. Check for other apps using the network. On Windows 11, press Ctrl + Shift + Esc to open Task Manager and look for apps with network activity. On macOS, open Applications › Utilities › Activity Monitor, then select Network. These views can help you find active apps, though their numbers are not a replacement for a speed test.
4. Pause cloud syncing temporarily. A backup or photo upload can use upload capacity even when the browser looks idle. Pause syncing from that app's own controls, run the test, then resume it.
5. Use the same connection each time. Stay in the same spot on Wi-Fi, or use the same Ethernet connection. Moving closer to the router or changing networks during the comparison makes it harder to isolate the effect of browser tabs.
6. Repeat the measurement. Run the test two or three times under the same conditions. If one reading is very different from the others, repeat it before treating it as a sign of a problem.

Why an idle tab can still matter

A tab does not have to be playing a video to affect a result. It might be downloading a file, syncing changes, refreshing a page or running a web app that regularly contacts a server. Browser extensions can also perform background work. In addition, a tab with a busy page can use processor time, which may slow down the test page on an older or heavily loaded computer.

There are two different effects to keep in mind. Network use can genuinely reduce the bandwidth available to the test. Browser background throttling, on the other hand, can affect how smoothly the test page runs without meaning your internet plan has suddenly become slower. Keeping the test page visible and pausing other traffic helps separate these causes.

If the result stays low with other network activity paused, test again over Ethernet if available. A large difference between Ethernet and Wi-Fi points toward the wireless connection or its location, while similarly low readings on both may warrant checking the router, modem or service provider.