Correction: > With right priorities for system services I was able to run hundreds and > thousands of B_NORMAL_PRIORITY threads without affecting UI responsiveness > too much and with smooth sound/video playback. Now I can even listen to music > in MediaPlayer and right-click-navigate FS while running 1000 Haiku3d's > background with no prob :) Actually not exactly 1000 Haiku3d's. You can run 1000 10-priority threads you can't run 1000 Haiku3d's because each will spawn 5 threads (app + window + render + app in app_server + window in app_server) and there is 4096 limit :) But you can run as much as system will allow you to.