AWS c6id.4xlargevsAWS c6id.8xlarge

c6id.4xlarge pairs 16 vCPUs with 32GB of RAM at $0.8064/hr On-Demand (about $581/mo at 24×7). c6id.8xlarge pairs 32 vCPUs with 64GB at $1.6128/hr (~$1161/mo). c6id.4xlarge is 100% cheaper per hour than c6id.8xlarge ($0.8064/hr gap).

Because both instances are in the **c6id family**, the only thing that changes between them is sizing — same silicon, same architecture (Intel Xeon (x86_64)), same burstable/sustained behavior. The choice is purely about how much capacity you actually need: c6id.4xlarge gives you 16 vCPUs and 32GB of RAM, c6id.8xlarge gives you 32 vCPUs and 64GB. 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.

On raw price-per-performance, the two are c6id.4xlarge delivers ~101% more single-thread Sysbench score per dollar (3679 vs 1832 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 (24767 vs 49572) are what to weigh. Spot pricing flips many of these comparisons — when c6id.4xlarge drops to $0.2901/hr and c6id.8xlarge drops to $0.6813/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick c6id.4xlarge when your workload is closer to compute-optimized (CPU-bound work — batch processing, web servers under sustained load, game servers). Pick c6id.8xlarge 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.