Bare Metal vs. AWS RDS: A Deep Dive into NUMA-Aware Tuning and PostgreSQL Performance

A real-world comparison across 7 environments, same workload, same hardware class, zero guesswork. When a client asked whether self-managed PostgreSQL on bare metal Kubernetes could replace their AWS RDS setup, I didn't want to answer based on intuition. So we ran the benchmarks ourselves — methodically, across seven environments, with the same scale factor and the same hardware class throughout. This article documents what we found, including a tuning discovery that cut baseline latency by 56% without changing a single piece of hardware. The Setup: 32-Core NUMA-Aware Beast To keep the comparison fair, all environments (Bare Metal vs Cloud) were allocated 2 vCPU / 8 GB RAM . However, there is a fundamental difference in the underlying "Metal." Our bare metal node is a powerhouse: 32 Cores (16 Physical Cores / 16 Hyper-Threading) NUMA-Aware Architecture Local SSD SAS Storage Unlike Cloud VMs (t3.large) that run on a hypervisor with "noisy neighbors," our Bare Metal allows the PostgreSQL