Why does Chrome's Incognito mode retrieve resources faster than the normal mode?

Question

I tested this from multiple machines (desktops and laptops) and OSes (Windows and Mac), and I can replicate the same behavior:
Resources are downloaded much faster in Incognito mode (not the rendering speed)

I could roughly think of two conditions under which Incognito and normal modes can be faster respectively:

• Incognito mode can be faster because it has no extensions.
• Normal mode can be faster because it caches the resource.

So I disabled all my extensions in normal mode and "reset" all the settings which deleted cache and browsing history, etc.

In all cases, when I looked at the Chrome inspector, resources are downloaded much faster in Incognito mode than in normal mode. Links load blazingly fast in Incognito mode.

Why is this a case?

Answer 1

I had the same problem and it turned out to be a caching problem. The same was also mentioned here: https://support.google.com/chrome/forum/AAAAP1KN0B0JRiv4Pyb8uE/?hl=no

Why does an incognito tab load a website much faster than a site opened normal tab?

I was able to achieve the same loading speed without the incognito mode by using this answer: Disable cache Chrome Extension (I made it work for all urls urls: ["<all_urls>"])

Disabling cache with webRequest has made it as fast as in the incognito mode.

Update: now with new hardware and an SSD it doesn't seem to make a difference for me.

Answer 2

I found the solution to this question. Apparently, clearing up cache and browser history through Chrome's Setting and disabling extensions through chrome://extensions is not enough.

If you're on macOS, type the command below (from https://superuser.com/a/318205):

rm -r /Applications/Google\ Chrome.app/
rm -r ~/Library/Application\ Support/Google/Chrome/
rm ~/Library/Application\ Support/CrashReporter/Google\ Chrome*
rm ~/Library/Preferences/com.google.Chrome*
rm ~/Library/Preferences/Google\ Chrome*
rm -r ~/Library/Caches/com.google.Chrome*
rm -r ~/Library/Saved\ Application\ State/com.google.Chrome.savedState/
rm ~/Library/Google/GoogleSoftwareUpdate/Actives/com.google.Chrome
rm ~/Library/Google/Google\ Chrome*
rm -r ~/Library/Speech/Speakable\ Items/Application\ Speakable\ Items/Google\ Chrome/

And then the cache will be completely cleared. Even after that, Incognito mode seems to be faster but it significantly increased the download speed of normal mode.

EDIT: I've unselected my answer because this did not solve the problem. After a few days, it slowed down again and without a proper benchmark, I'm not sure whether this had solved the problem in the first place.