Bufferbloat test (A-F grade)

The Bufferbloat test measures the single most common cause of real-world online-gaming lag: latency that spikes the moment your connection gets busy. It checks your ping while idle, then deliberately saturates your link — first download, then upload — and reports how much delay that added, with a clear A–F grade. Be warned up front: the honest fix is a router setting, not a PC tweak, and BRUTAL says so.

What bufferbloat is

When something on your network downloads or uploads at full speed — a game patch, a cloud backup, someone streaming — cheap router buffers fill up with data and your time-sensitive game packets get stuck waiting in line behind it. Your average ping might look fine on an idle test, then jump 100–300 ms the instant the link is loaded. That is bufferbloat, and it is exactly the rubber-banding and lag spikes you feel when your connection “is fine” on a speed test but terrible in a real match.

How the test works

BRUTAL follows the well-established Waveform / DSLReports method, using only standard HTTP and ICMP — no driver, nothing that touches anti-cheat:

1. Idle baseline: it pings Cloudflare (1.1.1.1) for a few seconds with nothing else running and records the median round-trip time.
2. Download saturation: it opens several parallel downloads from Cloudflare's speed endpoint to fully load your line, then measures ping again. The difference is your download bloat.
3. Upload saturation: it does the same with parallel uploads and measures the upload bloat.

The grade is based on the worst of the two directions — the added latency under load, not your idle ping.

Reading your grade

• A — under 30 ms added: excellent. Your connection stays responsive under load. No bufferbloat.
• B — 30 to 59 ms: good. Minor increase, fine for most gaming.
• C — 60 to 99 ms: moderate. You will feel lag spikes when others stream or download.
• D — 100 to 249 ms: high. Heavy lag under load.
• F — 250 ms or more: severe. Gaming while anything else uses the link will be very laggy.

How to run it

1. Open the Route Analyzer and click Bufferbloat.
2. The test takes roughly 20 seconds. The live log shows each phase — idle, then download saturation, then upload — with the measured bloat for each.
3. When it finishes, a graded card shows your letter grade, a plain-English summary, and the numbers: Idle X ms · Down Y ms (+bloat) · Up Z ms (+bloat).

For the most accurate result, run it when nothing else is using your connection — the test wants to be the only thing loading your link so it can measure the effect cleanly.

The honest fix: it is your router, not your PC

This is where BRUTAL refuses to lie to you. Bufferbloat lives in the buffers of your router or modem, not on your PC, so no registry tweak, DNS change, or “game booster” on this computer can remove it. The real, documented fix is to enable SQM / Smart Queue Management (the algorithms are called fq_codel or CAKE) on your router. Many modern routers have it under a name like “Smart Queue,” “QoS,” or “Bufferbloat,” and open-source firmware like OpenWrt supports it directly. BRUTAL's grade summary tells you exactly this for D and F results.

What you can do without router access

• Use a wired connection — Wi-Fi adds its own latency and loss on top of bufferbloat.
• Pause big transfers while you play — game updates, cloud sync, streaming. Less load means less bloat.
• Cap background uploads — upload bloat is often worse than download because home upload speeds are lower; backups and cloud sync are common culprits.
• Re-run the test after each change to see the grade move — the measurement is your honest before/after proof.

Common issues and troubleshooting

• “Test could not run (no internet?)”: the test needs a working internet connection to Cloudflare's speed servers. Check you are online and try again.
• Grade is worse than you expected: something else may have been using your link during the test. Close downloads and re-run when idle.
• Result shows “dropped” instead of a number: every ping was lost while the link was saturated — severe bufferbloat or packet loss. This is a strong signal to enable SQM on your router.
• Idle ping is high to begin with: that is base latency, not bufferbloat — use the Ping Test and Trace Route to investigate distance and routing instead.