CPU increase over time, and "sticks" at 100%

[Leon550]

Please bear with me while i do my best explaining this:)

I want to say first of all that I'm actually wondering if this is normal or not. Maybe it's just the way pro tools native works, and that my session is too heavy for my computer.

The reason i believe this is a problem, is that a session can play back at 35% CPU for a long time, but then after a while CPU usage increases, until it reaches 100% and stays there. What helps then, is to log out and start over. But it doesn't help for long.

Another soultion is of course to disable (in the session) some plugins. That helps. But if a session can play back at 35% CPU, the power shouldn't be a problem, right?

It's been like this for months, can't remember when it started.
It's the same problem if I disconnect all peripherals except iLok.

I made a video of my screen, that shows exactly what is happening, I would appreciate if you watched it (2min).

Here is the link:
https://www.youtube.com/watch?v=52bpco76OUw

And here is my sessions mix window.
https://i.imgur.com/e4awiLX.png

And my playback engine:
https://i.imgur.com/qI5Zda9.png

Troubleshooting I have done:

Unplugging ALL peripherals, except iLok
AHT
Ram test with Rember.app
Removing old plugins
Clearing PT prefs with cleaner app
Create a new partition on my projects drive (internal) install mountain lion and pro tools, and necessary software. I probably copied over some plugins. which leads me to believe that this may be a plugin problem.



System:

Macbook Pro 8,2 Late 2011 i7 2.4 GHz
10.8.5
16GB RAM
SSD System drive, HDD where the DVD used to be, for projects.
Pro Tools 10.3.9 Native

Peripherals (via hengedock):
3 LaCie Quadra FW800
M-audio Profire 2626 FW 400 (connected after HD's - daisychained)
3 USB Harddrives (via powered USB hub)
Dell Monitor
Apple keyboard and mouse
iLok 1 and iLok 2 dongles