Who would have thought, but changing Power Manager to High Performance helped. However I haven't tried multiple tracks, just Pigments and some audio samples.
It does. It's very important. In generel optimizing your PC for audio can help. That's why i suggest, you do so.
For some reason Cubase can't handle more than 3 voices, but I suppose it's not optimized for multiple cores for the latest CPUs (I read an article about it on Steinberg, they fixed it on CubX).
Standalone on the other hand, can handle 6 voices, but more are causing problems. It depends on presets, for example "PAD - Distant Generation" is very greedy for resources, even 3 causes pops.
I don't know about your cubase use CPU cores.
If you open your Windows ressource manager to see the activity of all your CPU cores, then you will see more load on a single CPU core. That's unfortunately how audio applications usuaaly work right now. That's why a CPU single core performance with virtual instruments is very important. Your CPU look like it have a very good singlecore base frequency. Higher than mine, and a newer CPU than mine.
Your soundcard performance also have an impact on the stress on your CPU.
As said - Pigments can like all quality sounding virtual synths be CPU demanding. The lovely preset you mention "PAD - Distant Generation", can be demanding, but i would say you should be able to run it without issues on your machine.
In generel lower notes can be more demanding than higher notes.
It is strange behavior though, as my PC is quite a horse, and if it can't handle a newly released virtual synth, well it must be really good one.
No not really - but annoying. As said - many quality virtual synths is quite demanding. It's suggested to render to audio or freeze tracks, when you have recorded to free CPU power.
If needed then using a buffer at 256 samples is'nt the end of the world. That is fine for many, especially when using virtual synth as you only have midi input time.
It's normal to raise the buffer much higher when mixing a project, to be able to run much more. The speed is most important when recording a plating performance.