Thats not unusual, since Linux likes to use any spare memory to cache disk blocks. If You want to have more Info about memory usuage of the single processes, then You might want to use the command top via commandline - this gives You also the memory usage of the different processes.
This is off topic, also especially since I'm using an N0503,
but I was wondering why my system is always so HOT. It's out in the open on my table, my CPU temp goes up to 58 degrees when nothing extra is running. At first i thought a process was doing something out of the ordinary hence thought maybe checking cpu/ram usage could isolate it but top shows nothing wrong.
The drives are also blazing hot, 50 degrees, very hot to touch. There is some HDD activity but nothing that's intense, the LEDs just blink once every 4-5 seconds. They aren't supposed to be so hot, they are Caviar Green drives.
Yea working with no problems 1600rpm in fact, air coming out is only slightly warm, the overall design of the ventilation on the n0503 is not very good if you look at it. I've even cut away the plastic grill strips at the rear exhaust.
The SATA/POWER connector riser card blocks airflow while the motherboard is tucked underneath with little air flowing over it.
I'm wondering if linux constantly checks the disks how do my disks ever go to sleep? My disks are perpetually hot even if there's nothing running.