Hello, @suneye1982,
Why the site speed is not good infact using the most optimized theme. Let me tell you.
All of our theme demos are very well optimized. Check here: https://gtmetrix.com/reports/xstore.8theme.com/fp10Fvt0/ When a user installs the theme on their server and imports the demo data user doesn’t need to optimize the site speed but when the user changes the demo content with his/her content, if their content is not optimized then he/she must need to optimize the content for better speed performance. We cannot provide our dedicated support for complete site optimization because it is covered in web development. I already shared all the possible ways with you but still if you are not able to solve your site speed issues. You can hire a third-party developer for this or If you want paid Customization services submit a customization request to WPKraken team.
Thanks for your understanding.
Regards 8Themes Team.