AWS r7iz.8xlargevsAWS r7iz.metal-16xl

r7iz.8xlarge pairs 32 vCPUs with 256GB of RAM at $2.9760/hr On-Demand (about $2143/mo at 24×7). r7iz.metal-16xl pairs 64 vCPUs with 512GB at $5.9520/hr (~$4285/mo). r7iz.8xlarge is 100% cheaper per hour than r7iz.metal-16xl ($2.9760/hr gap).

Because both instances are in the **r7iz 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: r7iz.8xlarge gives you 32 vCPUs and 256GB of RAM, r7iz.metal-16xl gives you 64 vCPUs and 512GB. 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 r7iz.8xlarge delivers ~99% more single-thread Sysbench score per dollar (1133 vs 569 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 (55293 vs 111395) are what to weigh. Spot pricing flips many of these comparisons — when r7iz.8xlarge drops to $1.2069/hr and r7iz.metal-16xl drops to $1.5672/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick r7iz.8xlarge when your workload is closer to memory-optimized (memory-bound work — in-memory databases, real-time analytics, large caches). Pick r7iz.metal-16xl when it's closer to memory-optimized (memory-bound work — in-memory databases, real-time analytics, large caches). 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.