The size of memory plays a role only when you don't have enough of it. If your scene (and all other programs you're running at the same time) fits in the available memory, there should be absolutely no difference between various RAM sizes.
There are other factors which come in play, because I guess the two builds you mention are not exactly identical. For example the RAM in the 96 GB build might be running on lower frequency or be configured in a way that not all the CPU memory channels are used. And that's talking just about memory, there can be many other factors affecting computer performance, not just hardware, but also any currently running software as well.
it turns out that the memory frequency plays a strong role for corona render ?
it turns out that the memory frequency plays a strong role for corona render ?
With Zen and Zen+ CPUs it afaik does. Zen 2 and Zen 3 not so much.
Imho what you are likely seeing here is that certain configurations have faster memory / proper multi-channel configs and possibly some sort of OC going on while others don't. I didn't own the 2990wx myself but if I recall correctly that particular CPU was very picky with not just the memory speed but also multi-channel setups. Do note that you can't really go higher than a certain RAM speed anyway because of the infinity fabric and how that works.
proper multi-channel configs are something new for me. I always thought this is the default behavior of the motherboard and they cannot be changed.
So what can I do?
Do I need to google how exactly to change the multichannel settings of specific motherboard?