Accuracy check

How accurate are speed tests?

The ISP in use delivers a download speed of 50Mbps. This test gives an indication of the standard deviation in the test results.

All tests have been done with Firefox on Linux. All speed tests are opened in a separate tab. The tests are done in rounds. Each speed test is tested once per lap. The first test is with Bandwidth Place, the second test is with Comparitech and so on. After testing the Xfinity xFi Speed Test (the last speed test to be tested), the second round begins with the same tests. There are a total of five test rounds.

Bandwidth Place

  1. 48.31Mbps
  2. 47.33Mbps
  3. 48.31Mbps
  4. 47.67Mbps
  5. 48.27Mbps

That gives an average of 48.0Mbps and a standard deviation of 0.45Mbps for the downloadspeed.

Comparitech

  1. 54.81Mbps
  2. 54.83Mbps
  3. 53.90Mbps
  4. 53.06Mbps
  5. 54.02Mbps

That gives an average of 54.1Mbps and a standard deviation of 0.74Mbps for the downloadspeed.

DSLReports

  1. 49.6Mbps
  2. 49.4Mbps

More tests were not possible. DSLReports reports that the instant download speed has dropped far below the running average :(

Fast

  1. 40Mbps
  2. 39Mbps
  3. 41Mbps
  4. 41Mbps
  5. 40Mbps

That gives an average of 40.2Mbps and a standard deviation of 0.84Mbps for the downloadspeed.

Fireprobe

  1. 51.06Mbps
  2. 50.70Mbps
  3. 50.80Mbps
  4. 49.77Mbps
  5. 48.09Mbps

That gives an average of 50.1Mbps and a standard deviation of 1.22Mbps for the downloadspeed.

Google Fiber

  1. 50.8Mbps
  2. 50.6Mbps
  3. 51.1Mbps
  4. 50.7Mbps
  5. 50.5Mbps

That gives an average of 50.7Mbps and a standard deviation of 0.23Mbps for the downloadspeed.

Internet Speed at a Glance

  1. 50..100Mbps
  2. 50..100Mbps
  3. 50..100Mbps
  4. 50..100Mbps
  5. 50..100Mbps

Measurement Lab

  1. 50.81Mbps
  2. 50.72Mbps
  3. 48.70Mbps
  4. 49.46Mbps
  5. 50.78Mbps

That gives an average of 50.1Mbps and a standard deviation of 0.96Mbps for the downloadspeed.

Ookla Speedtest

  1. 50.66Mbps
  2. 49.69Mbps
  3. 49.66Mbps
  4. 50.02Mbps
  5. 49.69Mbps

That gives an average of 49.9Mbps and a standard deviation of 0.43Mbps for the downloadspeed.

Sam Knows

  1. 50.9Mbps
  2. 50.7Mbps
  3. 46.3Mbps
  4. 45.4Mbps
  5. 50.3Mbps

That gives an average of 48.7Mbps and a standard deviation of 51,4Mbps for the downloadspeed.

Speed Of Me

  1. 56.23Mbps
  2. 56.28Mbps
  3. 56.18Mbps
  4. 55.59Mbps
  5. 55.99Mbps

That gives an average of 56.1Mbps and a standard deviation of 0.28Mbps for the downloadspeed.

SpeedSmart

  1. 56.61Mbps

SpeedSmart doesn't work fine within Firefox, other results given are unrealistic low.

Xfinity xFi Speed Test

  1. 51.0Mbps
  2. 50.8Mbps
  3. 50.9Mbps
  4. 50.9Mbps
  5. 51.0Mbps

That gives an average of 50.9Mbps and a standard deviation of 0.08Mbps for the downloadspeed.