Why is my Safari browser too slow and unstable?

To improve Safari's performance, follow these steps:

1. Update Safari and macOS.

2. Clear Safari's cache and history.

3. Test with different websites and remove problematic website data.

4. Reset Safari.

5. Check for network issues.

6. Create a new user profile.

7. Review system resources.

8. Reinstall Safari.

9. Disable experimental features in Safari.

10. Contact Apple Support if the problem persists. By following these steps, you should be able to troubleshoot and resolve Safari's slow performance issue.

Try running EtreCheck and posting its report in a reply to this Discussion.

Instructions: How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report - Apple Community

There are some good suggestions (as well as some that aren't as good), here: If Safari doesn't open a page or work as expected on your Mac - Apple Support. Please write back if nothing seems to help.

Hi. I have exactly the same problem. It appeared after last system update. Safari started to be very slow in some cases. The best way to see it is to open Facebook website and scroll down thru content. After some scrolling, Safari starts lagging a lot. I looked into RAM usage and it was about 3GB. I made same test on Firefox - problem there do not exist. It is also visible on YouTube website when you scroll videos with a tons of comments.