AWS c5.18xlargevsAWS c5.metal

c5.18xlarge pairs 72 vCPUs with 144GB of RAM at $3.0600/hr On-Demand (about $2203/mo at 24×7). c5.metal pairs 96 vCPUs with 192GB at $4.0800/hr (~$2938/mo). c5.18xlarge is 33% cheaper per hour than c5.metal ($1.0200/hr gap).

Because both instances are in the **c5 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: c5.18xlarge gives you 72 vCPUs and 144GB of RAM, c5.metal gives you 96 vCPUs and 192GB. 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.

Benchmark data for at least one of these instances is still being collected, so a direct performance-per-dollar comparison isn't possible yet. Sysbench scores are 1181/64417 for c5.18xlarge and pending for c5.metal. Check back as the benchmark queue completes — newer-generation instances typically score 10–30% higher on single-thread and 15–50% higher on multi-core vs the previous generation in the same series.

In practice, pick c5.18xlarge when your workload is closer to compute-optimized (CPU-bound work — batch processing, web servers under sustained load, game servers). Pick c5.metal 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.