Is there any RAM consumption per core? How much RAM to put, for example, for Ryzen 3900? I actually want to buy xeon e5 2678v3 12/24 (all instructions are supported), on intel as I heard you need L3 1mb, is it true? But the most important question is about RAM. Is there any dependence of RAM consumption on processor cores?
Each core works on 1M of data (2M in Monero), and also fetches things from the dataset which is 2G. Each NUMA node should have a copy of the dataset so that it can be read quickly by each mining thread (this is the default in XMRig).
Mining benefits greatly from faster memory, so you can get a performance boost spending a bit of extra time tweaking your frequency and timings.