Multisite only affects that if you are searching multiple blogs.
I'm just finishing a newer version, so far I got around 150% speedup (from an initial 2s to around 700ms). I figured out, that the main reason for the slow responsen is mainly the fact, that for each ajax request the whole WordPress core is loaded, which is usually slow as hell. I've found a nice tweak to minimize the resources needed to make this functional, however it needs a bit more testing.
I'm sending you a copy of this, you should experience huge speedups.
After extracting the zip file, please upload it to your server, overwriting the old search files, then open up the search you are using and save it, just so the new options get to the database. BACKUP THE OLD SEARCH FIRST!
Then open up the caching options tab, make sure, that the TimThumb option is enabled and save it.
Then do some testing, it should work much better, at least I hope so. If something goes wrong, use the backup 🙂Best,
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