It seems to be fundamentally the same deal except instead of passing `q` to GPT-4, they have some long-context "Memory Model" (whose details I've yet to fully understand). Also, MemoRAG uses a more conventional Retrieve/Generate pipeline downstream of the generated queries than "Contriever" (whose details I similarly haven't informed myself on).

It would be interesting to see a performance comparison, it certainly seems the most relevant one (that or an ablation of their "memory model" with the LLMs upon which they are based).