AWS m7i-flex.largevsAWS m7i.xlarge

m7i-flex.large pairs 2 vCPUs with 8GB of RAM at $0.0958/hr On-Demand (about $69/mo at 24×7). m7i.xlarge pairs 4 vCPUs with 16GB at $0.2016/hr (~$145/mo). m7i-flex.large is 111% cheaper per hour than m7i.xlarge ($0.1058/hr gap).

Because both instances are in the **m7i 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: m7i-flex.large gives you 2 vCPUs and 8GB of RAM, m7i.xlarge gives you 4 vCPUs and 16GB. 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 m7i-flex.large delivers ~120% more single-thread Sysbench score per dollar (34315 vs 15565 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 (3835 vs 6380) are what to weigh. Spot pricing flips many of these comparisons — when m7i-flex.large drops to $0.0410/hr and m7i.xlarge drops to $0.0902/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick m7i-flex.large when your workload is closer to general-purpose (balanced general-purpose workloads with a 1:4 vCPU-to-memory ratio). Pick m7i.xlarge 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.