Bufferbloat: why your ping explodes when someone starts streaming
UPDATED
Your ping is fine until someone downloads something, then it jumps to 300ms. That is bufferbloat. How to test it and how to fix it for good.
Your ping is 20ms. Then your roommate starts a Netflix stream or Steam starts an update, and suddenly it is 200ms and you can't hit anything. Your connection isn't “too slow”. It has bufferbloat.
What is happening
Routers and modems have buffers: queues where packets wait when the line is busy. Many devices have huge buffers and fill them completely. Your tiny game packet then has to wait behind megabytes of video in the queue. The bandwidth is fine, but the waiting time explodes.
How to test for it
You need to measure your ping twice: once with the line idle, and once while it is fully loaded. The difference is your bufferbloat. The Bufferbloat mode on Rekt-al Net does exactly that: 10 pings idle, then 10 pings while it downloads as fast as your connection allows.
| Extra ping under load | Grade |
|---|---|
| under 5ms | A+ |
| 5 to 30ms | A |
| 30 to 60ms | B |
| 60 to 200ms | C, noticeable in every online game |
| over 200ms | F |
How to fix it
- Enable SQM / Smart Queue Management. This is the real fix. Look for “SQM”, “Smart Queue”, “fq_codel”, “CAKE” or “Adaptive QoS” in your router settings. Set the limits to about 90 to 95% of your measured download and upload speed. The router then keeps the queue short and lets small game packets skip ahead.
- No SQM in your router? Many ISP routers don't have it. A gaming router with SQM, or an OpenWrt-capable router placed behind the ISP box, fixes it.
- Quick workaround: limit the bandwidth of the big downloaders (Steam download limit, streaming quality) while you play.
A VPN does not fix bufferbloat. The queue is in your own router or modem, before any VPN tunnel starts.