you case is small then you RMA not exceed 900MB??
I found 2~3GB RAM used in our case,HPxw8600 ,8 way,64GB RAM,
You don't have to do anything to access that amount of memory on XP Pro 64-bit. Keep refining the mesh and you will see the memory usage go up.
The CPU usage is a measure based on the total possible for all cores. If only one core (out of four) is being used fully, then the CPU usage will only report 25%.