E11 enterprise search performance

I’ve seen a significant performance hit on enterprise search in E11. Results take 5-9 seconds to show.
Compared to E10 (we still have our old environment available) where results take 0.5-2 seconds.

We ran performance diagnostic tool but no clues. All other programs work about the same.

I can’t find anything on improving speed, eg indexing settings etc.

We don’t have Enterprise Search Premium.

Any ideas? Thank you