Matt, > Any ideas? (Also, I've gotten a 2.6 speedup; hoping for more later > today. Then after the regridding is fast, I will attack IO.) Sorry for this ignorant question, but what is happening to make this RAMSES_tree? Why can't the count happen then? -- Stephen Skory s at skory.us http://stephenskory.com/ 510.621.3687 (google voice)