AWS m5n.4xlargevsAWS m5n.8xlarge

m5n.4xlarge pairs 16 vCPUs with 64GB of RAM at $0.9520/hr On-Demand (about $685/mo at 24×7). m5n.8xlarge pairs 32 vCPUs with 128GB at $1.9040/hr (~$1371/mo). m5n.4xlarge is 100% cheaper per hour than m5n.8xlarge ($0.9520/hr gap).

Because both instances are in the **m5n 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: m5n.4xlarge gives you 16 vCPUs and 64GB of RAM, m5n.8xlarge gives you 32 vCPUs and 128GB. 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 1058/13011 for m5n.4xlarge and pending for m5n.8xlarge. 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 m5n.4xlarge when your workload is closer to general-purpose (balanced general-purpose workloads with a 1:4 vCPU-to-memory ratio). Pick m5n.8xlarge 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.