FoundationDB single-core performance is fine. From my testing on the memory engine (and the docs), you can expect 70k+ reads/second/core for small keys and values. But crucially this means you must have concurrency to drive throughput.

No database can magically make your serial access pattern faster. Amdahl's law and all that.

FoundationDB's latency for your specific workload is up to how good you are at designing your algorithm for concurrency. If you do every step serially, you'll be spending most of your time waiting for the network.