[Brian Jones]

the noise on the back of the phone looks like GI animation noise. Check out CINEMA 4D/CINEMA 4D Prime/Render Menu/Edit Render Settings/Global Illumination/Tips and Tricks in the Help – it has a “GI and Animation” section near the bottom which has some good info.
The inside noise looks like it might be AO – turn up the AO settings (if that’s what it really is)
The glass edge “noises” look like they are either AO affecting a transparent material (never necessary) or it’s two surfaces occupying the same space. You have AO on scene wide which is never good when you have transparent materials and usually just slows things down for no need when you really only want AO in just a few materials – it’s mostly better to use AO in the Diffusion channel of a material rather than scene wide – if you feel you must have AO pretty-much scene wide use a Compositing tag on the transparent objects and un-check Seen By AO.
Do you really need GI? (answer may depend on how slow it’s going to get to defeat the noises caused by GI in animation)

[Brian Jones]

so no TP and assuming no x-particles and dynamics would be from a cloner/matrix/fracture object only so emission is more of a problem but basic particles have gravity and wind, just the value are not particularly world-scale especially the wind in relation to the emitter Speed but all values are keyframe-able, so totally doable in C4D

[Brian Jones]

here’s a modification using a simpler ‘feather’ object for testing. The feathers go in the xpGenerator which feeds them to the xpEmitter 9856_xparticlesemitobject2.c4d.zip

[Brian Jones]

those are x-particles with an x-particle shader? If so, then just add an xpGenerator object with the feather as a child of it

[Brian Jones]

have you successfully used keyframes before? From your description I can’t tell if you are using two keyframes or only one (and you have to have at least two). If it’s not that we’re going to need more info.

[Brian Jones]

there’s a lot of different grasses but this GSG tut does cover some interesting stuff using Hair (this is R13 pre-Grass object but the Grass object (tag) is more limited anyway).

https://greyscalegorilla.com/tutorials/make-grass-in-cinema-4d-using-hair/

[Brian Jones]

for what it’s worth with C4D hair as grass you can keep the hair from going through things with the hair collider tag

[Brian Jones]

and it appears to need VRay exclusively so I’m not seeing anything useful (not having VRay)

[Brian Jones]

it’s here https://boskolazovic.blogspot.ca (I haven’t had time to test it myself)

[Brian Jones]

sub d would slow the render a bit (depending on the level for preparation time) but shouldn’t be a killer.
Do you need Physical? Standard is a lot quicker in a very simple test (hard to tell without the actual scene though) – even with sampling turned up to match the Physical – I’m seeing 7 seconds vs 39.
Do you need scene wide Ambient Occlusion? It shouldn’t be doing much with the metal – if you need it on the cups put it only on the cups not scene-wide (though this won’t save as much time).