I have a Lenovo T430 laptop with 3.7GB of RAM. Since I started using this machine I observe the following strange behavior. If I do a lot of things, say have rails server running, a few nodejs processes, Spotify, Skype, but especially important - a lot of open tabs in Chrome, the system gets really sluggish. However in system monitor I see two things under memory and swap history:
- used memory is never more then 2.8 - 3GB out of 3.7;
- the swap is about 1.5-2 GB out of 4 GB;
So I am asking myself the following questions:
Why would the machine use the swap before the used RAM reaches something like 3.5 or 3.6 out of 3.7? Why would it swap so early?
If there is about 1GB of free RAM, why does it become sluggish?
Today I noticed something interesting though - right now system monitor shows 1.9GB of 3.7GB used memory, but the tool free -h shows the following stats:
total used free shared buffers cached
Mem: 3,7G 2,7G 967M 420M 8,9M 830M
-/+ buffers/cache: 1,9G 1,8G
Swap: 3,8G 0B 3,8G
So how comes there is this big difference of 1.9GB in system monitor vs 2.7GB in free -h. This leads me to the following conclusion - system monitor does not show all of the used memory, so apparently I run out of memory sooner than I see in system monitor, which explains the "early" usage of swap and the sluggishness of my computer. Am I correct?
P.S. I've set the swappiness to 10, but that doesn't help a lot.
freeand System Monitor agree on RAM usage excluding buffers and cache. – muru Sep 11 '14 at 07:06