Signifficant delay before site load, then site quickly loaded

Hello,

the site i manage have like 1-3 seconds (!) delay before it starts loading from me. THis is very bad, one get curious if website will load at all! And after these seconds, when site start loading, its done quite quickly.

So i would like to ask for help on how to debug cause of this on the server. Target is to make site start loading as soon even load time will be higher and cause more load on server. I think visitor must see site is trying to load as soon as possible.

here is the test:
http://www.webpagetest.org/result/140504_F1_JY1/2/details/

I have server root access. server Ph*p inf_o here

This is a test of a blank php page on same site (favicon is loaded):
http://www.webpagetest.org/result/140504_7G_KEX/

I will try to do any linux commands or anything you advice on to discover cause. [color=#2F4F4F]Thank you in advance[/color]

http://www.webpagetest.org/result/140505_T8_K2/1/details/

Address all the D and F grades by clicking on them, WPT tells you what is wrong.

On the waterfall chart at the link provided, notice everything seems to be going pretty well until call #42 and 43 are encountered. These are both third party calls and are slowing you down significantly.

On call #74 you are running into some time lost for hunting and resolving, because you have a extra / in the URL for the image.http://www.kvcwebhost.com/affiliate/banners//14.jpg

It’s one of the / right before the number 14, in the URL. You should only have one of these not two and it is making this element load slow and kick a 302 error.

Myself and some friends have a specialized forum for optimization of vBulletin HERE as well. Lots of successful cases, lots of tips and tricks located there. Slower first byte time is typical of vBulletin versions 4 and up, mainly because of the bloated database and code these versions use. But there are ways to get these closer to the target FBT.

It all starts though with cleaning up these D grades and F grades, first.