Sometimes dealing with big system ( 32 atoms ) < actually I don't think it is big but,,, anyway >

I found that in geometric optimization or other calculation with CASTEP, there are lot's of memory use during calculation, and computer don't appropriately use the CPU.

Now.. I'm doing with the two system of GaAlAs, and CPU using percentage is 20% and memory using percentage is almost 70~80%, so even I wanna do other job, i can't.

Please someone help me to deal with this problem.