AWS c8i-flex.largevsAWS c8i.large

c8i-flex.large pairs 2 vCPUs with 4GB of RAM at $0.0890/hr On-Demand (about $64/mo at 24×7). c8i.large pairs 2 vCPUs with 4GB at $0.0937/hr (~$67/mo). c8i-flex.large is 5% cheaper per hour than c8i.large ($0.0047/hr gap).

c8i-flex.large (compute-optimized, Intel Xeon (x86_64)) and c8i.large (compute-optimized, Intel Xeon (x86_64)) target different workload shapes. The vCPU:RAM ratios are different (2:4 vs 2:4), and depending on the architectures involved you may also see meaningful single-thread performance and per-hour-cost differences. This kind of cross-category comparison is most useful when you're early in the design phase and not yet sure whether your workload is CPU-bound, memory-bound, or balanced — once that's clear, the right pick is usually obvious.

On raw price-per-performance, the two are c8i-flex.large delivers ~5% more single-thread Sysbench score per dollar (37531 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 (3535 vs 3538) are what to weigh. Spot pricing flips many of these comparisons — when c8i-flex.large drops to $0.0268/hr and c8i.large drops to $0.0358/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick c8i-flex.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.