AWS i8g.16xlargevsAWS i8ge.12xlarge

i8g.16xlarge pairs 64 vCPUs with 512GB of RAM at $5.4912/hr On-Demand (about $3954/mo at 24×7). i8ge.12xlarge pairs 48 vCPUs with 384GB at $5.6952/hr (~$4101/mo). i8g.16xlarge is 4% cheaper per hour than i8ge.12xlarge ($0.2040/hr gap).

Both are generation-8 storage-optimized (NVMe SSD) instances, but they run on different silicon: **i8g.16xlarge** is AWS Graviton (ARM64), **i8ge.12xlarge** is AWS Graviton (ARM64). AMD variants (suffix `a`) are typically 10% cheaper than Intel siblings at comparable single-thread performance. Graviton variants (suffix `g`) are usually 20–40% cheaper but require ARM64-compatible binaries — most modern Linux stacks are fine, but verify any compiled extensions, native modules, or third-party binaries before migrating. Same vCPU/RAM ratio, same network performance class, different processor.

On raw price-per-performance, the two are roughly tied on single-thread performance per dollar (607 vs 585 Sysbench 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 (213062 vs 159753) are what to weigh. Spot pricing flips many of these comparisons — when i8g.16xlarge drops to $1.7150/hr and i8ge.12xlarge drops to $1.6710/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick i8g.16xlarge when your workload is closer to storage-optimized (NVMe SSD) (I/O-bound work needing low-latency NVMe local storage — NoSQL, search). Pick i8ge.12xlarge 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.