problem by site speed just on subdomain

[irwebco]

hello
i have a problem
any website on subdomain just on subdomain verry low speed
when move website on root directory problem resolve but on the subdomain low speed
when i check in gtmetrix in the timline see some load time is for first request for get url
i checked httpd.conf and optimie it too rebuild it but can't resolve this problem

os = cloudlinux
webserver = apache 2.2
php = 5.3.27

please help me for resolve this problem

 

[cPanelMichael]

Hello

Do you notice this across multiple accounts or is it isolated to a single domain name?

Thank you.