AWS m5dn.16xlargevsAWS m5dn.2xlarge

m5dn.16xlarge pairs 64 vCPUs with 256GB of RAM at $4.3520/hr On-Demand (about $3133/mo at 24×7). m5dn.2xlarge pairs 8 vCPUs with 32GB at $0.5440/hr (~$392/mo). m5dn.2xlarge is 87% cheaper per hour than m5dn.16xlarge ($3.8080/hr gap).

Because both instances are in the **m5dn family**, the only thing that changes between them is sizing — same silicon, same architecture (Intel Xeon (x86_64)), same burstable/sustained behavior. The choice is purely about how much capacity you actually need: m5dn.16xlarge gives you 64 vCPUs and 256GB of RAM, m5dn.2xlarge gives you 8 vCPUs and 32GB. AWS scales pricing close to linearly within a family, so picking the right size is mostly about right-sizing your workload, not getting a better deal per vCPU.

Benchmark data for at least one of these instances is still being collected, so a direct performance-per-dollar comparison isn't possible yet. Sysbench scores are pending for m5dn.16xlarge and 1092/6656 for m5dn.2xlarge. Check back as the benchmark queue completes — newer-generation instances typically score 10–30% higher on single-thread and 15–50% higher on multi-core vs the previous generation in the same series.

In practice, pick m5dn.16xlarge when your workload is closer to general-purpose (balanced general-purpose workloads with a 1:4 vCPU-to-memory ratio). Pick m5dn.2xlarge when it's closer to general-purpose (balanced general-purpose workloads with a 1:4 vCPU-to-memory ratio). When neither side is obviously right, the cheaper hourly rate usually wins for fault-tolerant batch workloads, while the higher single-core score usually wins for latency-sensitive web traffic. The regional pricing tables linked from each instance page below show where each is currently cheapest — sometimes a >20% regional gap flips the comparison entirely.