MongoDB 3.0 has significantly improved performance, especially write performance and hardware utilization compared to MongoDB 2.6. Throughput improvements were observed in various YCSB tests, with multi-threaded batch inserts showing a 7x increase, and balanced workloads seeing over 6x better throughput. Latency measurements also showed significant reductions in update latency by almost 90% at both the 95th and 99th percentiles. The optimal thread count for an application is between 16 and 64 threads, depending on whether it favors latency or throughput.