Marketing departments love "Mbps" (Megabits per second). It's a big number that sells subscriptions. But for a developer, a gamer, or anyone working remotely, bandwidth is often less important than latency and stability.
If you are trying to validate your ISP's performance, checking download speed is only 10% of the story. You need to look for the silent killers: Bufferbloat, Jitter, and Packet Loss.
1. The "Bufferbloat" Phenomenon
Modern routers use massive data buffers. When you max out your connection, these buffers fill up.
The Result: Your "Ping" packet gets stuck in line behind huge video packets. Your ping in-game might jump from 20ms to 500ms, even though your speed test still shows "100 Mbps."
How to Test for Bufferbloat:
Run a continuous ping to 1.1.1.1 while starting a large download. If your ping spikes significantly, your router suffers from bufferbloat.
2. Jitter: The Enemy of VoIP
Latency is the time it takes for a packet to travel. Jitter is the variance in that time. A single 150ms spike causes your voice to sound robotic on Discord or Zoom.
3. Technical Validation Steps
Stop using browser-based speed tests. Use terminal tools:
MTR (My Traceroute)
MTR combines ping and traceroute. It shows you exactly where packet loss is happening.
mtr -rw 8.8.8.8
Iperf3
Test raw TCP/UDP throughput without browser overhead.
iperf3 -c your-server-ip -p 5201
Summary
Don't settle for "fast but laggy." Validate your ISP connection by looking at load-latency and jitter.