Unity - Reduce RAM usage

Question

I know, this is quite "popular" topic, but I made some tests with Unity.

I would like to know why Ubuntu 16.04.2 LTS is using 2x more RAM than older versions of Ubuntu?

Is possible to reduce it to arround 500MB of RAM usage? Or is possible to downgrade Unity to lower RAM usage?

For imagine LUbuntu 16.04 LTS uses about 600MB of RAM with same kernel and packages, so it means that 400MB (+ something, because something of that 600MB RAM is LXDE in LUbuntu) of RAM is only Unity. In past release 400MB of RAM was almost whole oparating system Ubuntu with Unity, now it is only a part of Unity?

Please don't tell me to switch to lightweight flavour of Ubuntu, I have enough RAM and I like Unity, BUT I want to know why is it consuming 2x more RAM and of course I want to reduce it (from the principle).

So I made some tests with clean Ubuntu installations (with nothing running in the background) and their RAM usage:

Ubuntu 14.04.5 Trusty Tahr LTS

Ubuntu 15.04 Vivid Vervet

Ubuntu 15.10 Wily Werewolf

Ubuntu 16.04.2 Xenial Xerus LTS

Solution

Each new kernel supports more new hardware. Compiz continues to grow. Support for new features like snap. They all consume more memory. You can look at some of the specifics by using the top command in the terminal and sort on the memory column for details.

You might also try enabling low graphics mode using Compiz Configuration Manager, like so...

Comments

[tomsk]

Compiz usage is similar as in 14.04, 15.04 or 15.10. Yea new features like snap, but snap is not running in the background, it is running only if you install something.

[Boris Hamanov]

@tomsk no, snapd is running even if nothing has been installed. Other new processes probably exist too. Keep in mind that you're only asking for a 400K memory savings in a 8G RAM environment.

[tomsk]

So Low Graphics Mode I have set on since installation, yes but snapd (deamon) uses a tiny amount of RAM (like nothing) and top shows that compiz's RAM usage is 3%, XOrg's 1.5% and aptd 1.1%, but these numbers 1% is nothing it is a few MB, there is something what is consuming 2x more RAM (500MB) than olders Ubuntus.

[tomsk]

+ For imagine LUbuntu 16.04 LTS uses about 600MB of RAM with same kernel and packages, so it means that 400MB (+ something, because something of that 600MB RAM is LXDE in LUbuntu) of RAM is only Unity. In past release 400MB of RAM was almost whole oparating system Ubuntu with Unity, now it is only a part of Unity?

[Boris Hamanov]

Notice that the recommended RAM for 16.04.2 is 2G. See ubuntu.com/download/desktop

[tomsk]

Yea, but im not asking for recommended RAM :) im asking why is it consuming 2x more RAM and how can I reduce it or downgrade.. because there is nothing new in Unity in Ubuntu 15 and Ubuntu 16 so why it is consuming 2x more RAM? And that "new" feature that you can Unity set to bottom I dont use, I like panel of the left.

[Kaz]

> Each new kernel supports more new hardware. Yeah, but it has (1) the ability not to compile support for hardware that you don't have and (2) loadable modules.