fetching data slow

hi there I have a question
What might be the possible issue why the fetching of the data in my website is slow?

I have some conclusion:

1. is it in the proper management of table? currently my database is compose of 102 tables combination of modx tables and my own tables, my tables approximately have over a thousand records each. do you think this is the problem?I don't think so.

2. is it in table relation? I dont have enough knowledge regarding this manner so I think this might be the case.

3. is it in the query? I use xPDO query to fetch records from the database it compose of different joins.

I hope you get what I meant. I need some pointers regarding database and data manipulation in modx.
I hope you can help me. Im a newbie in web development in modx I know I have a lot of things to learn I want to start it right know..


thank you for reading this..

bump