I think you may have a backwards. Libcuckoo, CLHT, and TBB are widely used high performance C/C++ DRAM hash tables. I think TBB is the hash table Intel maintains, if I remember right.

So the DRAM experiments are apples to apples. It's actually the PMEM experiments, I think, that are comparing a new hash table on a new technology to previous hash tables that weren't designed specifically for that technology.