Ubuntu 9.10 high memory (RAM) usage?

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