In my company we are using jQuery UI Autocomplete 1.8.16 on one of our projects. We have a client where we grab the data from the database, but it takes a little bit longer than it should, around 310, 320 milliseconds. Of course, user is able to type faster than that. It creates the situation where the input text is being deleted and rewritten. 

One of the problems is, of course, the server side which works slower, but we can make it faster, and most likely we will. The second problem is, why does this happen at all? I am looking at source code of autocomplete widget and I just can't find what causes this behavior. Is this normal for every autocomplete widget in this situation, or is this just the case with some of them?

Thank you