AWS im4gn.4xlargevsAWS im4gn.xlarge

im4gn.4xlarge pairs 16 vCPUs with 64GB of RAM at $1.4552/hr On-Demand (about $1048/mo at 24×7). im4gn.xlarge pairs 4 vCPUs with 16GB at $0.3638/hr (~$262/mo). im4gn.xlarge is 75% cheaper per hour than im4gn.4xlarge ($1.0914/hr gap).

Because both instances are in the **im4gn 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: im4gn.4xlarge gives you 16 vCPUs and 64GB of RAM, im4gn.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 im4gn.xlarge delivers ~300% more single-thread Sysbench score per dollar (1928 vs 7710 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 (44647 vs 10937) are what to weigh. Spot pricing flips many of these comparisons — when im4gn.4xlarge drops to $0.4816/hr and im4gn.xlarge drops to $0.1076/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick im4gn.4xlarge when your workload is closer to general-purpose (general-purpose workloads). Pick im4gn.xlarge 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.