Hoi Alessio, according to http://babar-hn.slac.stanford.edu:5090/HyperNews/get/progQuestions/578.html and followups this could be due to 2x CPU limit as wall clock time. I am not exactly sure why this should affect your job (since I have had many jobs with a CPU/wall clock time ratio of < 0.5). Maybe splitting into more files could help? Cheers, --U.