Testing a website Without "WWW"

Hi Guys
when i was testing my website without “WWW”, the test results are much worse comparing when i use the WWW whitin my site address.
do anyone know why it happens?
i appreciate your help

If your website are www required,
the cdn or load balancer will spend a little time to redirect your request without ‘www’ to ‘www.xxx.com’, before response html document.
the “First Byte” maybe worse.