PlayInfoBox

Home /Network /What Is Bufferbloat? Why Only Games and Video Calls Lag

What Is Bufferbloat? Why Only Games and Video Calls Lag

Your speed test says everything is fine, but games and video calls still stutter β€” here is the real reason, and how to fix it.

What bufferbloat actually looks like

Your speed test shows the exact speed you are paying for, yet the moment another device on the same connection starts a large upload or download, your game's ping spikes or your video call's voice and video start breaking up.

The cause: an oversized buffer

Modems, routers, and carrier equipment all include a buffer β€” a temporary holding area for data that arrives faster than it can be sent. When that buffer is set larger than it needs to be, data piles up and waits its turn once the connection is saturated, and latency can spike from a normal few milliseconds to several hundred or even a few thousand.

Throughput and latency are different measurements

A speed test measures maximum throughput (Mbps), while the responsiveness you actually feel in a game or call depends on latency (ms) β€” a separate metric. Bufferbloat is unusual because it leaves your maximum throughput untouched while making latency spike specifically under load.

How to actually test for it

A normal speed test won't reveal this β€” you need a tool that specifically measures "loaded latency," comparing your idle ping against your ping while an upload and download are running at the same time. Dedicated bufferbloat test tools grade the difference on a scale (often A through F).

The fix: Smart Queue Management (SQM)

Turning on SQM (Smart Queue Management) β€” available on many modern routers and open-source firmware β€” or a queue algorithm like CAKE or fq_codel, and setting your bandwidth limit slightly below your line's actual speed, lets the router manage the order traffic is sent in, preventing the buffer from ever filling up excessively.

How to turn SQM on in your own router

Look for a menu labeled QoS, SQM, or "Smart Queue Management" in your router's admin settings, usually under a Network or Advanced tab. Once you find it, set the upload and download bandwidth limits to roughly 85-95% of your line's real, tested speed rather than the plan's advertised number β€” leaving that small headroom is what lets the router actually manage the queue instead of just filling it. If your current router's firmware doesn't offer this menu at all, open-source firmware such as OpenWrt, or a newer router built around a modern queue algorithm, is the more direct fix.

Ping and console matchmaking issues are often related

If you want to check raw latency by itself, separate from bufferbloat, running a basic ping test to a nearby, well-known server gives you a baseline idle latency number to compare against your loaded-latency results. On game consoles specifically, a restrictive NAT type can cause similar-looking symptoms β€” trouble joining matches or connecting to other players β€” even when bufferbloat is not the culprit, so if matchmaking problems persist after fixing your queue management, checking your console's NAT type setting is the next logical step.

Frequently Asked Questions

Will upgrading to a faster internet plan fix this?

Increasing your throughput can reduce how often your connection gets saturated, which helps somewhat, but it doesn't remove the underlying cause β€” an oversized buffer. A queue management setting like SQM is a more direct fix.

Can I fix this without replacing my router?

Some newer routers already ship with a modern queue algorithm active by default, but many older routers or carrier-issued modems don't support SQM at all. In that case, switching to a router that supports SQM, or flashing open-source firmware that does, is the practical solution.