AWS is4gen.4xlargevsAWS is4gen.medium

is4gen.4xlarge pairs 16 vCPUs with 96GB of RAM at $2.3052/hr On-Demand (about $1660/mo at 24×7). is4gen.medium pairs 1 vCPUs with 6GB at $0.1441/hr (~$104/mo). is4gen.medium is 94% cheaper per hour than is4gen.4xlarge ($2.1611/hr gap).

Because both instances are in the **is4gen family**, the only thing that changes between them is sizing — same silicon, same architecture (arm64), same burstable/sustained behavior. The choice is purely about how much capacity you actually need: is4gen.4xlarge gives you 16 vCPUs and 96GB of RAM, is4gen.medium gives you 1 vCPUs and 6GB. 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 is4gen.medium delivers ~1387% more single-thread Sysbench score per dollar (1220 vs 18136 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 (44652 vs 2548) are what to weigh. Spot pricing flips many of these comparisons — when is4gen.4xlarge drops to $0.7214/hr and is4gen.medium drops to $0.0178/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick is4gen.4xlarge when your workload is closer to general-purpose (general-purpose workloads). Pick is4gen.medium when it's closer to general-purpose (general-purpose workloads). 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.