# How to properly define %maxcore in ORCA

The %maxcore parameter in ORCA gives the memory per core needed for a calculation, however it is unclear to me if this should be the entire memory available to the job or if it should be some percentage of the max memory.

How would I define %maxcore if I have a node with 64GB of memory, slurm allocates 32GB of the memory to me, and I have 4 cores. Presumably it would be set to 8000 to assign 8GB to each core, but I have seen calculations fail with out of memory errors when doing this that I would not predict would have this problem.

The ORCA Input Library website has a list of commonly encountered errors that discusses using the maxcore option.