GNOME.org

System Monitor

System Monitor shows you what programs are running and how much processor time, memory, and disk space are being used.

Monitoring the CPU

Check how much processor (CPU) capacity is being used
The amount of CPU being used tells you how much work the computer is trying to do.
Is it normal for my computer to be using this much CPU or memory?
If the computer is doing a lot of work, it will use more processor time and more memory.
Why do I have more than one processor?
Computers with more processors find it easier to run many programs at the same time.

Memory usage

How much memory is being used?
The Resources tab tells you how much of your computer's memory (RAM) is being used.
Using memory maps
View the memory map of a process.
What is "swap" memory?
Swap memory allows your computer to run more applications at the same time than will fit into the system memory (RAM).

Questions about processes

Kill (close) a program immediately
If a program stops working or freezes, you can force it to close.
What do the process statuses mean?
The status of a process can be running, sleeping, stopped, or zombie.
What is a process?
A process can be manipulated from the process list.
Why are there processes listed that I did not start?
Lots of system processes run automatically in the background.

Common tasks with processes

Change the priority of a process
Decide whether a process should get a bigger or smaller share of the processor's time.
Find which program is using a specific file
Search for a file that's open to display which process is using it.
List which files a process has open
View files being accessed by processes.
Make the information update faster or slower
Refresh the information shown in the System Monitor with a longer or shorter interval.
Which program is making the computer run slowly?
Sort the list of processes by % CPU to see which application is using up the computer's resources.

Information about file systems

Check how much disk space is being used
The File Systems tab shows how much space is being used on each hard disk.
Learn what the File Systems information means
Explanations of all of the fields shown in the File System tab.
Show all file systems, including hidden and system ones
There are hidden file systems that the operating system uses.
What are the different devices in the File Systems tab?
Each device corresponds to a partition on a hard disk.

Network information

Show the network speed in bits instead of bytes per second
Choose the units to display your network speed.

Miscellaneous

Get the same information from the command line
Information in System Monitor can also be found using command line tools.
Is GiB the same as GB (gigabyte)?
Units of measure for memory and disk space
What is Solaris mode?
Use Solaris mode to reflect the number of CPUs.