Hey Lucas, here is a part of a conclusion from Puget:
There are some applications (Photoshop and NeatBench from what we tested) that can to potentially get up to ~13% higher performance with DDR4-3600 RAM. Just keep in mind that this performance is definitely not "free" - just like CPU overclocking, it is possible that it may cause more problems than the extra performance will solve and may require a bit of tinkering in the BIOS to get it stable over the life of your system.
If you ask me - the cost gains and troubles from 64gb is not worth it over the quantity of 128gb. Maybe, just maybe, you could look for 2666 if thats applicable.
Your answer fully corresponds with the answer I have received from Pudget systems.
I have emailed them today and I will copy and paste the reply I have received from Pudget for those who interested.
Always, always, always go for more RAM over higher speed. The difference in speed will not be perceptible, period.
It would be like you asking a question and getting your answer in a billionth of a second vs 1.25 billionths of a second. You just wouldn't even be able to tell. Maybe if doing large amounts of RAM intensive scientific calculations it would make a difference, but even then, its minimal at best.
After Effects in particular likes large amounts of RAM. 64 would probably be fine for either program, but if it's about speed vs amount go with amount.
It is important to match the RAM speed to the max supported by the CPU. Going over won't benefit you and can cause instability. What CPU are you planning on using?
The main factor for both programs is the CPU - After Effects is predominantly single threaded and likes CPU speed, and so does the design and animation side of C4D.
Rendering, however is more dependant on high core counts. How much rendering do you plan to do?
Live view is about RAM, that's where the previews are stored, and more is better.
I hope that helps. Let me know if I can answer any other questions.