AWS i4i.4xlargevsAWS i4i.xlarge

i4i.4xlarge pairs 16 vCPUs with 128GB of RAM at $1.3730/hr On-Demand (about $989/mo at 24×7). i4i.xlarge pairs 4 vCPUs with 32GB at $0.3430/hr (~$247/mo). i4i.xlarge is 75% cheaper per hour than i4i.4xlarge ($1.0300/hr gap).

Because both instances are in the **i4i 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: i4i.4xlarge gives you 16 vCPUs and 128GB of RAM, i4i.xlarge gives you 4 vCPUs and 32GB. 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 i4i.xlarge delivers ~301% more single-thread Sysbench score per dollar (2163 vs 8673 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 (24436 vs 6155) are what to weigh. Spot pricing flips many of these comparisons — when i4i.4xlarge drops to $0.6587/hr and i4i.xlarge drops to $0.1135/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick i4i.4xlarge when your workload is closer to storage-optimized (NVMe SSD) (I/O-bound work needing low-latency NVMe local storage — NoSQL, search). Pick i4i.xlarge when it's closer to storage-optimized (NVMe SSD) (I/O-bound work needing low-latency NVMe local storage — NoSQL, search). 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.