3 ms·

These 151/92 Mbps numbers are almost certainly flawed results because speedtest.net is a very poor tool to measure high-bandwidth connections. Let me show you

by mrb 15y ago

These 151/92 Mbps numbers are almost certainly flawed results because speedtest.net is a very poor tool to measure high-bandwidth connections. Let me show you why. I was in Tokyo in August 2009 at my sister's house. She had 100Mbit/s to the internet. I could easily reach close to the maximum theoretical bandwidth by downloading multiple kernel images from jp.kernel.org, at 95+ Mbps. However speedtest.net would only give me download speeds of 50-60 Mbps. My system was running Linux, so I ran top, and saw speedtest.net's Flash app (npviewer.bin) at 100% CPU... it was being bottlenecked by the CPU! It was an old Pentium 3 1.2GHz, but still. Even a modern 2-3GHz CPU core is only about 3x-4x faster. Bottom line, speedtest.net, due to the high overhead of the Flash VM, is a very poor choice to benchmark high network speeds, as it is CPU-constrained at about 150-200Mbps even on a modern CPU, which is exactly the number reported by this Google fiber user. I am shocked that no one knows this.

bobbles 15y ago
Sorry but I'm having a hard time believing that any modern CPU would only be 3-4x faster than a Pentium 3 1.2GHz. Just generally looking at the difference between levels of modern processors in something like 3D mark vantage http://www.tomshardware.co.uk/charts/desktop-cpu-charts-2010/3DMark-Vantage-High,2418.html http://www.tomshardware.co.uk/charts/desktop-cpu-charts-2010... shows massive performance differences. If I'm missing something obvious here let me know
- quantumhobbit 15y ago
  The flash app is probably only running in one thread and therefore only one core without any hyperthreading and doesn't take advantage of modern vectorized instructions. Moving from 1.2 GHz to 3.6GHz will give you a 3 times speedup. So sounds about right.
  - mrb 15y ago
    Exactly. Speedtest.net does not take advantage of the multiple CPU cores.
deleted 15y ago
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jrockway 15y ago
Yeah. In my experience, speedtest doesn't even run properly on netbooks. It's one of the worst pieces of software ever written. I use iperf: http://iperf.sourceforge.net/ http://iperf.sourceforge.net/

by mrb 15y ago

bobbles 15y ago

Sorry but I'm having a hard time believing that any modern CPU would only be 3-4x faster than a Pentium 3 1.2GHz. Just generally looking at the difference between levels of modern processors in something like 3D mark vantage http://www.tomshardware.co.uk/charts/desktop-cpu-charts-2010/3DMark-Vantage-High,2418.html http://www.tomshardware.co.uk/charts/desktop-cpu-charts-2010... shows massive performance differences. If I'm missing something obvious here let me know

quantumhobbit 15y ago
The flash app is probably only running in one thread and therefore only one core without any hyperthreading and doesn't take advantage of modern vectorized instructions. Moving from 1.2 GHz to 3.6GHz will give you a 3 times speedup. So sounds about right.
- mrb 15y ago
  Exactly. Speedtest.net does not take advantage of the multiple CPU cores.

deleted 15y ago

[deleted]

jrockway 15y ago

Yeah. In my experience, speedtest doesn't even run properly on netbooks. It's one of the worst pieces of software ever written. I use iperf: http://iperf.sourceforge.net/ http://iperf.sourceforge.net/