Throttling vs. Congestion: How to Tell the Difference

The Sherlock Holmes of Bandwidth

It's frustrating. You pay for 500Mbps, but in the evenings, you get 50Mbps. Is it malice or incompetence?

Test 1: The VPN Check

Run a speed test. Then, turn on a trusted VPN (like Mullvad or Proton) and run it again.

• If speed INCREASES with VPN: You are being Throttled. Your ISP detected high traffic (like a download) and artificially slowed it down. The VPN hid the traffic type, bypassing the throttle.
• If speed stays SLOW: It is Congestion. The physical cables in your neighborhood are saturated. A VPN cannot fix a traffic jam.

What to do about Congestion?

Complaint. Call your ISP. Complain to the FCC (in the US). Congestion means they oversold your node.