there is an algo that is incredibly RAM intensive
There is indeed. It's called Cuckoo Cyclehttps://github.com/tromp/cuckoo
Whereas 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 byhttps://forum.z.cash/t/breaking-equihash-in-solutions-per-gb-second/1995