Solidrocks only uses 2 cores in a quad core pc

Hello!
Can you tell me please, why when I use Solidrocks presets and render, Max only uses 2 cores, and when I use personal settings without solidrocks, Max uses 4 cores?

Thank you!

Max

More information:
- I´m rendering an animation.
- I made the LightCache (flytrough) and IrradianceMap (multiframe incremental) with the Solidrocks parameters in my dual core pc and store each in files.
- I´m rendering one part in the dual core and other part in a cuad core (loading the IM and LC files)

The problem is in the cuad core as I write before, Max is using only 2 cores.

Thanks!

MAx