Some weird behavior:
1) I have a scene with some cloth objects;
2) set a portion of timeline with SET START anf SET END FRAME;
3) hit LOOPING preview, everything goes fine (60fps stable) until it reaches the END frame, then it FREEZES for 1-20 seconds depending on the complexity of cloths (no cloths, freeze);
4) Unchecked visibility of Soft Cloth stuff: still freezing;
5) unchecked Rigid Body Simultation and Soft Cloth SImulation: still freezing;
6) deleted animation and left model in T position: it freezes;
7) DEactivated phisycs in any cloth then it loops smoothly
then I think it is due to some extra work for cpu/gpu BUT:
8) I checked on performance monitor and everything goes down (unused) during the freeze, no usage spike anywhere...

Please help, please...