How to fix bufferbloat on your router
Turn on smart queue management, set the right limits, and test again.
Last verified: 8 November 2026. Menu names and paths change with firmware, so check your model's manual if a step looks different.
The short answer
Run the bufferbloat test to get your real speeds. Then turn on smart queue management (often called SQM, CAKE, fq_codel or Smart Queues) and set download and upload limits to about 90% of what the test measured (85–95% is the usual range). Test again: you are aiming for an A.
Menu names change between firmware versions. If you can't find an option, search your router's help pages for "SQM", "smart queue" or "QoS".
Where to find it on common routers
| Router | Where to look | What to set |
|---|---|---|
| OpenWrt | Install the luci-app-sqm package, then Network → SQM QoS | Your WAN interface, queue cake with piece_of_cake.qos, limits at 85–95%. Turn off hardware flow offloading, or SQM won't work |
| UniFi gateways | UniFi Network → Settings → Internet → your WAN → set Advanced to Manual → Smart Queues | Turn on and enter speeds slightly below your tested ones. Ubiquiti designs it for connections under about 300 Mbps |
| ASUS | Adaptive QoS → QoS → Enable QoS, then pick a QoS type (Adaptive or Traditional) | Enter your tested speeds. Asuswrt-Merlin firmware adds CAKE on supported models |
| eero | eero app → Discover → eero Labs → Optimize for Conferencing and Gaming | Turn on. It's a beta feature that eero says works best under 500 Mbps |
| Netgear Nighthawk | Advanced → Setup → QoS Setup, or Dynamic QoS on the Basic home screen (varies by model) | Turn on Dynamic QoS. Netgear says QoS isn't needed on connections of 300 Mbps or more |
| GL.iNet | Firmware 4.9 or later: admin panel → Flow Control → SQM. Older firmware: Advanced Settings (LuCI) → Network → SQM QoS | Same as OpenWrt. SQM and GL.iNet's QoS can't run together, and SQM turns off Network Acceleration |
Menu paths last checked November 2026 against OpenWrt's SQM guide, Ubiquiti's help center, ASUS's QoS FAQ, eero's blog, Netgear's knowledge base and GL.iNet's docs.
Provider-supplied routers rarely offer smart queue management. If yours does not, the usual fix is a router that does, connected behind the provider's box in bridge or modem mode.
Tuning the limits
- Run the test with nothing else using the connection and note download and upload.
- Set the limits to about 90% of those numbers.
- Retest. If the grade is still B or worse, lower the limits by 5% and test again.
- Once you reach A or A+, try raising them a little until the grade starts to slip, then step back.
For what each grade means, see the bufferbloat test and how Speedhound grades it.
More guides
- Why is my Wi-Fi slow?Find out whether the problem is your Wi-Fi, your router or your provider, in five checks.
- How to boost your Wi-Fi signalPlacement, bands, channels and hardware fixes, cheapest first.
- Best Wi-Fi channel for 2.4, 5 and 6 GHzWhich channels don't overlap, when to avoid DFS, and how wide to go.
- Mesh Wi-Fi vs a single routerWhen mesh is worth it, and when one good router or an access point is better.
Related
Questions
Does fixing bufferbloat reduce my speed?
Slightly. Smart queue management works best with limits set a little below your real speed, so you give up roughly 5–10% of peak speed in exchange for steady, low latency under load.
Which router is best for bufferbloat?
Any router that supports CAKE or fq_codel smart queue management. OpenWrt-based routers and UniFi gateways are common choices among people who care about latency.
Why is my bufferbloat grade still bad after turning on QoS?
Usually the limits are set too high, so the queue still forms in the modem. Lower both limits to about 85–90% of your tested speeds (and on OpenWrt check that hardware flow offloading is off), or set the shaper to the speed you actually get, not the plan speed.
More from Speedhound
- Speed testDownload, upload, ping, jitter and bufferbloat in 20 seconds.
- Bufferbloat testSee how much lag your connection adds under load.
- Download time calculatorHow long a file takes at your speed.
- Good internet speedHow many Mbps you need for your household.
- Good pingWhat ping, jitter and packet loss numbers mean.
- GuidesStep-by-step fixes for slow Wi-Fi, lag and bufferbloat.
- ToolsIP, ping, DNS, port, subnet and Wi-Fi QR tools.