Why Netrunner so heavily uses CPU ?

I noticed that it relies more on a CPU than a memory (unlike Kubuntu). Why is that ?

Which release Standard (14, 15, 16) or Rolling are you referring to?
Also, what drivers for your GPU are you using, opensource or proprietary?

I tried 14 and 16 Standard, tried opensource and proprietary (processor microcode firmware for Intel), on several laptops (with AMD and Intel). For example it can load CPU to ~80-90% while VLC plays movie.

As it uses the same drivers and graphicsstack as ubuntu and kubuntu there should be not much difference when it comes to cpu usage.
CPU usage might be higher when swapping as it compresses stuff into ram (zram) though on a modern CPU these compression algorithms should not eat up CPU time.

Do you only had that issue with VLC? If yes maybe it chooses a cpu intense video output. Maybe changing it to opengl or xv will help in that case.

Not only with VLC - it is an example. This always happens when I’m doing something (Netrunner loads CPU heavily when it is not in idle). Much more than Kubuntu. My CPU are modern: Lenovo G565, Dell Inspirion 3542.

Can you take a look if it is a specific process eating up CPU and if it might be related to desktop effects.
Can you turn off desktop effects and see if it affects the CPU usage.

And can you give us a detailed example with cpu numbers that you tested on Netrunner and Kubuntu so we can make a comparison on our end?

Current working application always loads CPU most.
(I used Kubuntu 15.04 and Netrunner 16)
CPU load while opening Firefox:
Kubuntu - 85 %;
Netrunner - 100%.

CPU load while playing video in Firefox:
Kubuntu - 20 %;
Netrunner - 40%.

CPU load while opening Dolphin
Kubuntu - 60-80%;
Netrunner - 80-90%.

But sometimes CPU loading in Netrunner can be twice more than in Kubuntu.
Bad case of playing video in Firefox:
Kubuntu 34-35%
Netrunner 59-65%

Bad % while idle:
Kubuntu 2%;
Netrunner 11-13%;

On rolling version CPU loads heavily too (last screen, right side of the graphic - opening Firefox).

Maybe the kernel or some other package in the mix makes Netrunner 16 use more CPU on your machine/gfx setup.
How about trying Netrunner Rolling and see if its any better, so then there is a good chance that upcoming Netrunner Kubuntu version is also likely to perform better with your setup?

From the 3rd and 4th screenshot I see that swap is used. The CPU spikes are explainable if zram compression happens. This eats for a short time your cpu time.

Why it doesn’t happens in Kubuntu ?

Kubuntu does not use zram by default.