Bounce dropouts heavy plugins DP8

[Galileo]

hi there
we have 2 studios with almost the same setup here, and by both systems have exactly the same problem on the same project:
setup:
MacPro mid 2012 /12 core 2.66 GHz
16 GB Ram
500 PCI SSD systemdisk/startupdisk
1 TB Raid 2 recording disk
DP 8.07 on 64bit mode

one system runs with a PCI 424 MOTU HD 192 / 48 kHz/ 24 bit / 1024 buffer size Audio Interface
the other FW 800 MOTU 896 Mk3 Hybrid / 48 kHz/ 24 bit / 1024 buffer size Audio Interface

on booth systems we have the same dropout by bouncing audio at the same time stamp by using heavy plugins, like OZONE 6, OZONE 5, Brainworx bx_XL V2 and PSP Neon HR.
screenshot: http://grab.by/CHTE
lower buffer size = worse result = more dropouts
by mergin the audio no more dropouts / but this is not realy a good solution!

i tested the same project in another studio with a quad core MacPro and DP8.07 and these plugins and it was reproduceable.

can anyone give us sugestions how to remove this bug?

thx G.