On my pc, tasks "de_nbody_orphan_test_2model_4_..."
are running on my two cores at the same time suspending the other tasks on the second processor(core).

My conf :
AMD X2 Dual cores proc
Boinc mgr 6.12.19
no GPU available
Running on 100% processor
using 70% of time processor

Hope this will help
Thxs

The new app is multithreading (see the 'mt' at the end if the exe name).
It is written to work that way. If you want it to run on 1 core only like the previous app, you need to use an app_info.xml and set nthreads=1 in there. For that see the n-body 0.40 thread in the news section.

Ok I understand it, but in my mind, boinc should run in a "set and forget" mode, able to live with other boinc project and running in a very low priority.

In this idea multi-threaded app should run on one core at time by default.
The app_info.xml should be used to set a non-standard mode (in a boinc point of view) like using a few core at the same time.

Do I'm wrong ?

OlaV+++

Ok I understand it, but in my mind, boinc should run in a "set and forget" mode, able to live with other boinc project and running in a very low priority.

In this idea multi-threaded app should run on one core at time by default.
The app_info.xml should be used to set a non-standard mode (in a boinc point of view) like using a few core at the same time.

Do I'm wrong ?

OlaV+++

BOINC instructs it how many threads to use. It's usually a more effective use of your processor to have the single task running on all cores than running separate things on each CPU. The BOINC scheduler should swap it for other tasks at different times, so it's not like it should be preventing other tasks from ever running. If you set it to a number of threads < number of CPUs, it should use some number of CPUs for it, and put other jobs on the remaining CPUs.