I mean, hard no on both claims. A memory cache (even memcached, which might not be state of the art) stomps all over the performance claims of SSDB. Memcached can do ~250kqps on one core, roughly depending of exactly what kind of cores are in question, and can typically turn around a request in < 50µs. SSDB is only "just as fast" if the rest of your stack is so insensitive to performance that you can't measure an order of magnitude difference in service latency.