In that case, I strongly recommend switching to the index table engine – especially if you have a lot of items to search for. Don’t forget to switch to the index table engine when the indexing is finished.
If you have over 10 000 items to index, then I usually suggest only indexing the titles only – as the content and the excerpt may generate a lot of unneccessary search data – if the titles are descriptive.
This configuration will give you the best possible relevant matches for the keywords for the titles.