Here is some information to help you better understand the memory consumption of PlanningForce / OnePMO.
When you schedule by day, we create a memory allocation by day, tasks and resources.
We can describe the memory footprint as follows:
Allocations Qty = Tasks Qty * Resources Qty * Days Qty
It becomes obvious that when planning hour, this rule becomes:
Allocations Qty = Tasks Qty * Resources Qty * Days Qty * 8 Hours a day (depending on the number of hours of work describing a day in your preferences)
In theory, one therefore finds that the memory increases a report 8.
In reality, this ratio will be lower, because scheduling interval is not exclusively hour.
For optimal planning, it is advisable to define a scheduling interval in hours, after this time, you can plan the day, then weekly and finally monthly.