I think maybe, you just misunderstood something with PC memory. If you have the feeling that your models consume too much memory you can always see in the F11 panel under "nx" if youre right or not.
The task manager can not tell you the memory used by your model. Model memory is inside the nexus, and inside the video card memory. It does not show in the task manager. The task manager only tells you the memory assigned to a process.