I've just been through a batch of upgrades to upgrade my home server from Ubuntu 8.04 to Ubuntu 9.10.

Now I am using 9.10 I notice that the system is using a lot of the available RAM. I have 1GB installed and about 800MB are being used immediately after reboot. The system has a web server, ftp server and samba server running, used by my family. These shouldn't account for the high memory usage.

Is there anything I can try?

Chandler, March 2010

All modern OS tend to use as much of the available RAM as possible. So, using about 80% of the RAM is normal, in fact, it actualy tryes to use 100% of it.
Much of that useage comes from cached data.

This makes the system more effecient.

The reason for that is that it's 1000's times faster to access what is in RAM than the fastest hard drives.

Then, when any application actualy need part of that RAM, the OS will automaticaly flush some of the RAM to accomodate the running application.

Electro, April 2011