WordPress installation in a sub folder

Hello,

I have two installations of WordPress on installed in public_html folder that maps to http://heroleads.com/ and another installation that maps to http://heroleads.com/thailand/

I followed the instructions https://codex.wordpress.org/Giving_WordPress_Its_Own_Directory

The instillation in the sub folder is extremely slow, the problem comes loading the first byte which takes around 15 seconds. I stopped all the plugins and changed the theme to twenty fifteen the problem remained.

I change .htaccess settings and premainks settings but the problem remains what could be the issue?