How to fix bufferbloat

The short answer

Turn on your router's Smart Queue Management (SQM) feature, sometimes called Smart Queues, QoS or a gaming/conferencing optimization, and set it to slightly below your real Internet speed. Then test again: the delay while your connection is busy should drop a lot. If your router has no such setting, a router that supports SQM is the most reliable fix.

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Before you start

Confirm you have bufferbloat. Include the speed test. If your response time rises a lot while the connection is busy, keep reading. If not, see what else can cause lag.
Write down your measured download and upload speeds. You'll need them in step 3.
Know how to log in to your router. It's usually through the router's app, or a web address printed on a label on the router.

Step 1: Find the setting

Router makers call this feature different things, and menu names change between models and updates. Look for:

SQM or Smart Queue Management
Smart Queues
QoS (Quality of Service), especially "Adaptive QoS", "Dynamic QoS" or "Traditional QoS"
"Optimize for gaming", "Optimize for conferencing and gaming", or similar wording in mesh Wi-Fi apps
Bandwidth control or traffic shaping

It's usually under Advanced, Internet, WAN, or Traffic settings. If you can't find it, search for your router's model name plus "SQM" or "QoS".

Some "QoS" features only prioritize certain apps or devices and don't fix bufferbloat on their own. Features based on SQM, fq_codel or CAKE are the ones designed to keep queues short.

Step 2: Turn it on

Enable the feature. If it asks for a mode or algorithm and offers CAKE or fq_codel, choose one of those.

Step 3: Set the speeds just below your real speed

Most SQM settings ask for your download and upload speed. Enter about 85–95% of what you actually measured, not your plan's advertised speed. This keeps the line inside your router, where SQM can manage it, instead of letting it build up in your modem.

Start at about 90%.
If bufferbloat is still there, lower it a little (to 85%, then 80%).
If everything is great, you can try a little higher to win back speed.

Some routers measure this automatically. That's fine, but check the result with a test.

Step 4: Test again

Run our test again with the speed test included. Our results page compares it with your last run. You're looking for a big drop in "Slowdown when busy", ideally to under 30 ms. Your top speed will be slightly lower; that's the trade-off, and it's usually unnoticeable.

If your router can't do it

Routers supplied by your Internet provider often don't offer SQM. You can usually use your own router behind the provider's, or ask the provider to put theirs into "bridge mode" so your router handles everything.
A router that supports SQM (or a mesh system with a gaming/conferencing optimization) is the dependable fix.
In the meantime: pause big uploads and downloads while gaming or on calls, and schedule backups and updates for overnight.

Questions people ask

Will SQM slow down my Internet?

Slightly: setting it below your real speed costs a few percent of top speed. In return, games, calls and browsing stay responsive while others download, which most people notice far more.

Is QoS the same as SQM?

Not always. Many QoS features just prioritize chosen devices or apps, which may not fix bufferbloat. SQM keeps every queue short, which is what fixes it. Some routers use the word QoS for an SQM-style feature, so testing before and after is the best way to know.

Do I need to do this on every device?

No. It's a router setting, so it helps every device on your network at once.

Last updated October 17, 2026.