Correlation between cores and RAM?

Thinking (drooling) ahead for the new Mac Pro (2018/2019), I am looking at the processing bottleneck on my existing 6-core 32 GB RAM MacPro 2013 (trashcan). Processors are frequently solid at 100% for all 12 hyper-threaded cores. Memory pressure is always in the green.

To speed things up, I will need more cores. The new one is rumored to go up to 28–32 cores. Given that I currently do not run into memory issues, does that indicate that 32 GB RAM should be enough? Or is there some rule of thumb that RAM should be scaled to number of cores? Say if 6/32 is a good combo, then it should not be 32/32, but 32/128?