Tools
Bufferbloat test explained
Why ping spikes when someone downloads, how Nexus grades it, and what actually fixes it.
A normal ping test runs on a quiet connection. Games don't. When someone on your network streams, downloads or uploads, a router with oversized buffers queues your game's packets behind that traffic, and your ping jumps. That's bufferbloat.
What the test does
Open Gaming › Network & Ping and select Run bufferbloat test. Nexus:
- measures ping while the connection is idle,
- measures ping while downloading,
- measures ping while uploading,
and grades how much the ping rises over idle. It takes about 30 seconds and uses up to 100 MB of download and 25 MB of upload over HTTPS (Cloudflare's speed test by default; change it in Settings). The upload sends generated filler, never your files.
Grades
| Grade | Ping increase under load |
|---|---|
| A+ | less than 5 ms |
| A | 5 to 30 ms |
| B | 30 to 60 ms |
| C | 60 to 200 ms |
| D | 200 to 400 ms |
| F | 400 ms or more |
Download and upload are graded separately. The overall grade is the worse of the two. If ICMP ping is blocked on your network, Nexus measures TCP connection time instead and says so.
What fixes a bad grade
Bufferbloat happens in your router or modem, so no Windows setting can fix it. What helps:
- Turn on SQM or Smart Queue (fq_codel or CAKE) in your router, if it has it.
- Or cap your router's speeds slightly below your plan's.
Run the test again afterwards to see the difference.
Other network checks
The same page measures latency, jitter and packet loss to your router and to the internet separately, so you can tell a Wi-Fi problem from an ISP or server-distance problem. It also has DNS timing and switching, Wi-Fi details, traceroute and an HTTPS download test.