What is holding up First Byte

[NDCC]

Hello - just looking for a little help with what is going on with the waterfall and slowing the TTFB: http://www.webpagetest.org/result/150609...5/details/

Time to first byte is ~700ms. We have tried making various changes but kept breaking things on the site

We have a dedicated server.
Server Info:-
PHP Version 5.3.28
Apache Server: 2.2.23 (Unix)
Apache Cpanel: v3.18.0 rev9999
OS: Linux CENTOS 6.6 x86_64 standard
Processors: 8 x Intel Xeon E31230 @3.20GHz (Cache 8192kb)
RAM: 4096MB DDR3
We use Incapsula as CDN.

We also have a WP blog running off the same server that gets a clean sweep of A's: http://www.webpagetest.org/result/150529...984a3743a/