Try applying these changes: https://github.com/q2a/question2answer/pull/910
If you want to apply additional performance improvements at the expense of not being able to search for posts (like not updating the qa_words table), that will boost performance more.
But please, DO let me know the times things take BEFORE these changes and AFTER these changes. To properly test it, do this:
- Backup your current file (the one with those changes)
- Replace it with the official standard file
- Run the tests I mentioned in the comment above and take a note (you can measure using the web browser inspector, in the networking tab you'll see the requests)
- Apply the changes from my pull request
- Execute step 3 again
- Share the results here
Obviously, if you then want to apply more changes, go ahead. The thing is that these changes won't sacrifice any feature, while more "aggressive" changes, will.