Apr 18, 2016

How does Google’s Data Saver extension for Chrome decrease the amount of data used?

I have had the Data Saver extension for Chrome enabled for the past week on my Chromebook. After 6 days, it shows that I have used 4.1% less data with Data Saver versus “normal” browsing. How does it use less data? I don’t really notice any difference...everything looks the same and load speeds seem to be unchanged.
FYI, I've used Data Saver on both a Chromebook and on a Nexus 6, and in my experience it saved much more data on a mobile device. I'm not sure why....maybe mobile websites lend themselves more to compression for some reason.
When enabled, http traffic (currently doesn't apply to https or incognito windows) is routed through Google's servers and is compressed using SPDY protocol. It reduces image quality, some services such as geo-location.

Here's Google's warning on what side effects you might run into:
•Some websites might not be able to accurately determine your location.
•Some images might look a little fuzzy.
•Internal websites, such as your company’s internal sites, might not load.
•Sites that your mobile carrier uses to authenticate and bill you might not work. For example, you might have trouble logging in to your mobile phone provider's website.
•Local settings will be ignored if you manually modified your /etc/hosts file.
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