After Effects CS4 Octocore 2008 render problem

[Manware]

Hi all, I have a problem with speed rendering on CS4 suite.
I try to explain my problem:
In preferences menu is enabled multiprocessing. When I launch a render all cores works at plenty charged but in a few minutes the cores stopped and only one core work.
My machine is a octocore 2,8 with 16GB ram on snow leopard sytem.

Any suggestions?

Thanks :)

[Manware]

Maybe I found the solution.

After effects CS4 with problems with multicore render:

On preferences panel, click cmd+alt+shift and then click on "general". With this shortcut key you will enable a secret option.
check the first option and put "0" and ok.
I tested with this option and renders are ok, all cpus at top of speed rendering.

Cheers :)