AWS i8ge.12xlargevsAWS i8ge.18xlarge

i8ge.12xlarge pairs 48 vCPUs with 384GB of RAM at $5.6952/hr On-Demand (about $4101/mo at 24×7). i8ge.18xlarge pairs 72 vCPUs with 576GB at $8.5428/hr (~$6151/mo). i8ge.12xlarge is 50% cheaper per hour than i8ge.18xlarge ($2.8476/hr gap).

Because both instances are in the **i8ge family**, the only thing that changes between them is sizing — same silicon, same architecture (AWS Graviton (ARM64)), same burstable/sustained behavior. The choice is purely about how much capacity you actually need: i8ge.12xlarge gives you 48 vCPUs and 384GB of RAM, i8ge.18xlarge gives you 72 vCPUs and 576GB. 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.

Benchmark data for at least one of these instances is still being collected, so a direct performance-per-dollar comparison isn't possible yet. Sysbench scores are 3333/159753 for i8ge.12xlarge and pending for i8ge.18xlarge. Check back as the benchmark queue completes — newer-generation instances typically score 10–30% higher on single-thread and 15–50% higher on multi-core vs the previous generation in the same series.

In practice, pick i8ge.12xlarge when your workload is closer to storage-optimized (NVMe SSD) (I/O-bound work needing low-latency NVMe local storage — NoSQL, search). Pick i8ge.18xlarge 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.