Multiple instances of Blue Cat's MB-5 causes glitchy audio

I have been looking for a solution to this problem since purchasing the MB-5 over 6 months ago.
 
The MB-5 plug-in operates fine with a single instance, but as I add more instances to a project it begins to introduce glitches into the audio.  Offline mixdown is fine, but the real-time audio becomes unusable.  Task Manager shows processor usage stays low and evenly distributed across all 8 logical processors. Typically Processor usage>20%, Disk usage >25%, and >4 of 16G ram in use.
 
Result is the same with both the VST and DX plug-in
As latency is increased, the problem is diminished.
Result is the same with delay compensation disabled
Also, curiously, if the plug-in windows are open, even if in the background, the problem is lessened, and in some cases eliminated.
 
System config is as follows
 
Sonar Producer X3e
Windows 8 Pro x64
Intel i7-3770K at 3.5/3.9GHz
16GB 1600Mhz Dual channel DDR3 ram
RAID level-0 with 2 Seagate 7200RPM hybrid drives
MPEX-1394-B3 Firewire 800x2 400x1
MOTU Traveler  Firewire audio interface
MOTU Ultralite Firewire audio interface
 
Any input you may have would be much appreciated.
 
Regards,
              DiDi

Good suggestion scook.  I will try that later today when I fire up the DAW.
 
Thanks,
            DiDi

I don't own MB-5, but I have noticed that certain types of plugins create significantly more latency than others - and adding multiple instances of a latency inducing plugin will increase the latency impact.   
 
How high are you setting your buffers when the issue lessens?  I sometimes increase my buffers to 2400 or sometimes even 4800 with several latency-inducing plugins loaded to ensure smooth audio.  Whereas when tracking, I remove all latency sensitive plugins and am able to lower buffers down to 64.