AWS c6in.24xlargevsAWS c8a.24xlarge

c6in.24xlarge pairs 96 vCPUs with 192GB of RAM at $5.4432/hr On-Demand (about $3919/mo at 24×7). c8a.24xlarge pairs 96 vCPUs with 192GB at $5.1730/hr (~$3725/mo). c8a.24xlarge is 5% cheaper per hour than c6in.24xlarge ($0.2702/hr gap).

These are different generations of the same series. **c8a.24xlarge** is the newer generation, and AWS's pattern across generations is fairly consistent: ~10–15% better single-thread, 15–30% better multi-core, and similar or modestly higher per-hour pricing — so the price/performance per dollar usually improves with each generation. **c6in.24xlarge** is still available and still works (AWS doesn't retire instance types quickly), but for new workloads the newer generation is typically the better default unless you have a specific reason to pin to the older AMI or there's a meaningful regional pricing advantage today.

On raw price-per-performance, the two are c8a.24xlarge delivers ~98% more single-thread Sysbench score per dollar (547 vs 1082 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 (148602 vs 484870) are what to weigh. Spot pricing flips many of these comparisons — when c6in.24xlarge drops to $1.5442/hr and c8a.24xlarge drops to $1.6649/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick c6in.24xlarge when your workload is closer to compute-optimized (CPU-bound work — batch processing, web servers under sustained load, game servers). Pick c8a.24xlarge 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.