there is an algo that is incredibly RAM intensive

There is indeed. It's called Cuckoo Cycle

https://github.com/tromp/cuckooWhereas Equihash (as parametrized in Zcash) uses 200 bits of memory to store a hash,

Cuckoo Cycle doesn't store hashes explicitly, but maintains 1 bit for each pair of hashes.

Where Equihash solves problems of size a few million with a few hundred MB, Cuckoo Cycle

can tackle problems of size a few *billion* with the same memory thanks to a vastly

more intensive use of memory.

The reference implementation has been broken by

https://forum.z.cash/t/breaking-equihash-in-solutions-per-gb-second/1995