AWS r5d.2xlargevsAWS r5d.large

r5d.2xlarge pairs 8 vCPUs with 64GB of RAM at $0.5760/hr On-Demand (about $415/mo at 24×7). r5d.large pairs 2 vCPUs with 16GB at $0.1440/hr (~$104/mo). r5d.large is 75% cheaper per hour than r5d.2xlarge ($0.4320/hr gap).

Because both instances are in the **r5d 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: r5d.2xlarge gives you 8 vCPUs and 64GB of RAM, r5d.large gives you 2 vCPUs and 16GB. 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 r5d.large delivers ~290% more single-thread Sysbench score per dollar (1898 vs 7403 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 (6685 vs 1589) are what to weigh. Spot pricing flips many of these comparisons — when r5d.2xlarge drops to $0.3031/hr and r5d.large drops to $0.0714/hr, the cheap-per-hour winner can swing meaningfully.

In practice, pick r5d.2xlarge when your workload is closer to memory-optimized (memory-bound work — in-memory databases, real-time analytics, large caches). Pick r5d.large 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.