Ubuntu – Difference between the results of the top command and System-Monitor,Why

command linesystem-monitortop

Why is there a huge difference between the outputs' of top command and the system monitor when both programs were run at the same time. Please find attached is the screen shot showing the huge difference:-

See the Ram usage, in GUI it just shows 1.1G whereas in CLI the usgage climbs upto 3.2G

Is this a bug?

Best Answer

If you are referring to RAM usage, it is because system monitor does not include buffers and caching, just actual Ram used to run applications, top is slightly confusing because it does not obviously show disk usage after buffers / caching. Try using the following command : 

free -m

See the image below, and note that the second line of free -m indicates available Ram, whilst the first line indicates actual Ram usage including disk caching.

enter image description here

I would recommend installing and using htop as it is better and simpler than top in my opinion.

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