AWS c7a.mediumvsAWS c7a.xlarge

c7a.medium pairs 1 vCPUs with 2GB of RAM at $0.0513/hr On-Demand (about $37/mo at 24×7). c7a.xlarge pairs 4 vCPUs with 8GB at $0.2053/hr (~$148/mo). c7a.medium is 300% cheaper per hour than c7a.xlarge ($0.1540/hr gap).

Because both instances are in the **c7a family**, the only thing that changes between them is sizing — same silicon, same architecture (AMD EPYC (x86_64)), same burstable/sustained behavior. The choice is purely about how much capacity you actually need: c7a.medium gives you 1 vCPUs and 2GB of RAM, c7a.xlarge gives you 4 vCPUs and 8GB. 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 c7a.medium delivers ~270% more single-thread Sysbench score per dollar (77728 vs 21015 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 (3915 vs 16796) are what to weigh. Spot pricing flips many of these comparisons — when c7a.medium drops to $0.0086/hr and c7a.xlarge drops to $0.0684/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick c7a.medium when your workload is closer to compute-optimized (CPU-bound work — batch processing, web servers under sustained load, game servers). Pick c7a.xlarge when it's closer to compute-optimized (CPU-bound work — batch processing, web servers under sustained load, game servers). 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.