Hi,
When you accetp choice the system takes the default value as per the SUM tool. If you want more option you can choose other configuration.
It depends on the no of object and the memory needed for those objects. When you see the shadow instance profile you should see some parameter as PHYS_Memory which is controlling the memory parameters.
If you want to increase the speed you need to also check the parallelism note and see how many processes to be assigned to increase the through put.
Thanks
Rishi abrol