AWS c8gn.largevsAWS c8i.large

c8gn.large pairs 2 vCPUs with 4GB of RAM at $0.1185/hr On-Demand (about $85/mo at 24×7). c8i.large pairs 2 vCPUs with 4GB at $0.0937/hr (~$67/mo). c8i.large is 21% cheaper per hour than c8gn.large ($0.0248/hr gap).

Both are generation-8 compute-optimized instances, but they run on different silicon: **c8gn.large** is AWS Graviton (ARM64), **c8i.large** is Intel Xeon (x86_64). 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 c8i.large delivers ~27% more single-thread Sysbench score per dollar (28169 vs 35749 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 (6518 vs 3538) are what to weigh. Spot pricing flips many of these comparisons — when c8gn.large drops to $0.0369/hr and c8i.large drops to $0.0350/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick c8gn.large when your workload is closer to compute-optimized (CPU-bound work — batch processing, web servers under sustained load, game servers). Pick c8i.large when it's closer to compute-optimized (CPU-bound work — batch processing, web servers under sustained load, game servers). 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.