Bufferbloat: why your gigabit feels slow

You bought a gigabit plan. The speed test reads 940 Mbps. Yet your Zoom call still freezes when someone uploads a file. Welcome to bufferbloat.

What is it?

Bufferbloat is excess latency caused by oversized network buffers. When a buffer fills up, every new packet has to wait in line — sometimes for hundreds of milliseconds. Throughput stays high, but latency under load explodes.

How to detect it

Run a speed test while pinging a known-good server in another tab. If ping jumps from 10 ms to 200 ms during the download phase, you have bufferbloat.

How to fix it

• Enable Smart Queue Management (SQM) on your router — most modern firmware supports it.
• Switch from FIFO queueing to fq_codel or CAKE.
• If your ISP gateway is the bottleneck, put it in bridge mode and use your own router.

The fix is almost never "more bandwidth."