Yes, Odoo uses the wkhtmltopdf library to print pdf reports, and it has many performance issues, especially when dealing with large pdf files with complex header and footer.

Please refer to this blog post for more information on conf file parameters:

https://www.rosehosting.com/blog/how-to-speed-up-odoo/

In Technical -> System Parameters,  make sure that web.base.url points to the correct port number. 

Hope this helps you.

Thank's it is was a helpful gide!!