AWS m8gn.largevsAWS m8gn.medium

m8gn.large pairs 2 vCPUs with 8GB of RAM at $0.1455/hr On-Demand (about $105/mo at 24×7). m8gn.medium pairs 1 vCPUs with 4GB at $0.0728/hr (~$52/mo). m8gn.medium is 50% cheaper per hour than m8gn.large ($0.0727/hr gap).

Because both instances are in the **m8gn family**, the only thing that changes between them is sizing — same silicon, same architecture (AWS Graviton (ARM64)), same burstable/sustained behavior. The choice is purely about how much capacity you actually need: m8gn.large gives you 2 vCPUs and 8GB of RAM, m8gn.medium gives you 1 vCPUs and 4GB. 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.

On raw price-per-performance, the two are m8gn.medium delivers ~93% more single-thread Sysbench score per dollar (22880 vs 44231 points per $1/hr). That's the cleanest signal we have for "which one runs your workload faster per dollar," but it only matters if your workload is single-thread-bound; for parallel workloads the multi-core scores (6513 vs 3177) are what to weigh. Spot pricing flips many of these comparisons — when m8gn.large drops to $0.0463/hr and m8gn.medium drops to $0.0160/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick m8gn.large when your workload is closer to general-purpose (balanced general-purpose workloads with a 1:4 vCPU-to-memory ratio). Pick m8gn.medium 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.