How to tell if a new router fixed bufferbloat

You replaced your router, but calls or games still lag when someone downloads or uploads. A faster speed test result does not necessarily mean the lag is gone: bufferbloat is extra delay that appears when the connection is busy.

Compare the old and new router under similar conditions with the Bufferbloat Test. It measures how much response delay grows during downloads and uploads, then gives a grade from A+ to F.

Compare the old and new router

1. Open the Bufferbloat Test on the same computer you used before the router change, if possible.
2. If you still have the old router, connect it as you did before and run the test. Note the grade and the delay increase during downloads and uploads. If you did not save an old result, you cannot make a direct before-and-after comparison, but you can still check the new router and compare its settings.
3. Connect the new router and run the test again. Keep the computer, location, internet plan, and connection type the same. For a Wi-Fi comparison, use the same room and band if you can identify it.
4. Repeat each test three times. Keep other devices off large downloads, video streams, cloud backups, and game updates while testing. Compare the typical results, not just the best run.
5. Look at both the grade and how much delay rises during downloading and uploading. A higher grade with a smaller delay increase is a stronger sign of improvement than a higher download speed alone.

The test exchanges network test data with our server to measure the connection under load. It does not need access to your files.

What the result means

The new router gets a better grade and less delay under load

The connection is responding more consistently while busy, so the new router likely reduced bufferbloat in the conditions you tested. If video calls and games also feel smoother during downloads, that supports the result. It does not guarantee the same performance in every room or at every time of day.

The grade is similar, or delay still rises sharply

The router may not have reduced bufferbloat, or another part of the connection may be limiting the result. Check whether the new router has a traffic-management feature such as QoS or Smart Queue Management. The names and options vary by model.

The grade changes a lot between runs

Something else may be using the connection, or Wi-Fi conditions may have changed. Repeat the tests when the network is quiet. If results still vary, test with a wired connection to separate Wi-Fi interference from delay elsewhere in the network.

You only have a result from the new router

A single grade shows how the connection behaves now, not whether the router fixed a previous problem. If lag remains, you can compare the router's traffic-management settings on and off, changing one setting at a time. Treat that as a useful check, not a substitute for an old-router baseline.

How to get a fair comparison

1. Keep the test computer and connection type the same. Do not compare an old router tested over Ethernet with a new router tested over Wi-Fi. If you need to check the connection type, open Settings › Network & internet in Windows 11 and select Wi-Fi or Ethernet. On macOS, open System Settings › Network and select the active connection.
2. Pause other network activity. Stop streaming, large downloads, cloud syncing, and game updates on every device you can. Background traffic can make a good router look worse, or hide the improvement you are trying to measure.
3. Test wired before blaming Wi-Fi. Connect the computer to the router with Ethernet and repeat the test. If the wired result is better, the router may be managing internet traffic well while Wi-Fi signal, interference, or distance is affecting wireless use. If the computer has no Ethernet port, use the same Wi-Fi position for every run.
4. Try the router's traffic-management feature. In the router's app or administration page, look for QoS, SQM, Adaptive QoS, or a bandwidth limit. If you change a setting, retest with it on and off while keeping other conditions the same. If the router asks for upload and download limits, use measured real speeds as a starting point and leave some capacity unused. The right values depend on your connection.
5. Update and restart the network equipment. Install a stable firmware update for the router, then restart the router and modem if your internet provider's instructions allow it. Run the test again after the connection settles. Avoid changing several router settings at once, or you will not know which change mattered.

When the router may not be the cause

If a wired test through the new router still shows a large delay increase, the cause may be the modem, your internet provider, or traffic elsewhere on the network. Try the test at a different time of day, especially if the connection is shared with many people in your home. If performance is consistently poor, ask your provider whether there is a service issue or whether your plan has limits that affect busy connections.

A router can improve latency under load without increasing your plan's maximum speed. The most useful comparison is the change in delay and grade under the same test conditions, not the router's advertised top speed.