Sync causing browser decreased performance

Description of the issue:
I’ve noticed that for some time now my browser was slow on certain sites, such as Facebook or Ad libraries for Google And Meta. So I decided to reinstall my browser fresh. Then I added it back to sync with my other laptop. But the issue persisted.
I’ve found out by elimination that it’s caused by some of the sync options and some not.

To be honest I have no idea why theses sites didn’t work like they were supposed to, but I guess to know that you were able to reproduce it you’d need such indicator. I don’t see other ways of seeing if this occurs.

So far I’ve noticed that I can sync simple things such as:

  • bookmarks
  • settings
  • reading list
  • saved tab groups.

And Everything still works, but whenever I go above that, or decide to sync everything the browsers efficiency drops dramatically.

**Steps to Reproduce: **

  1. Connect a fresh instalment on a device to an existing sync chain.
  2. Either turn on sync everything, or (one or more) of other elements to sync that cause this issue.
  3. After refreshing the website, the sync has negatively affected the performance of the same websites that worked flawlessly before connecting to the sync chain.
    Reproduces how often:

I’ve tried it multiple times and it’s the same every time, even after resetting the system OS to a clean state.

Brave Version(See the About Brave page in the main menu):
Version 1.71.123 Chromium: 130.0.6723.116 (Official Build) (64-bit)

Type of devices currently running on the Sync chain in question:
Laptop, Mobile device, and a PC(where the issue occurs)

Might help, to also report your computing devices’ Operating Systems, along with actual hardware names (because hardware acceleration info may also help).

Brave Support team member @Mattches is probably the go-to guy for this one.

@Jakub_I if you sync everything except for extensions, does the issue happen? Guess to be very specific, are you adding/using any extension when having the problem?

Doesn’t matter which?

How so? What happens?

To be clear, no issues on the laptop or mobile device?