My test of Google Cloud CDN is not as good as cdnperf.com

Firstly I see https://www.cdnperf.com/ and its result. It seems Google is the 2nd fastest CDN provider in the world. Even for different continents, its speed is among the top 3.

Then I perform test by myself, by using Google Cloud Storage Bucket and then create a https load balaner and then enable CDN and create the frontend.

My Google CDN settings are:

  1. Cache static content
  2. Client TTL set to 1 day. Default and Max TTL set to 30 days.

Then I try to use Uptrends.com to perform the test. Which will download files from Google CDN from 227 checkpoints of Uptrends servers(the default selected checkpoints in their system) around the world. To my surprise:

  1. For a 12.2MB exe file, its speed is faster than Azure for many times, but not always.
  2. For a 24.6kb png image file, its speed is much slower than Azure, Cloudflare.

I check this and it seems Google will add overhead for each connection, which may explain why a smaller file does not have a good performance.

But in cdnperf, it said ""Performance" is the time it took for a user to download a 500byte image from a CDN.". So it is also testing on a rather small file(500 byte).

Why my result is so different from those from cdnperf? Am I doing something wrong?

I then recheck cdnperf for how it gets the performance, and it said ""Performance" is the time it took for a user to download a 500byte image from a CDN.", so its result is also for a small file.