AWS r6a.48xlargevsAWS r6a.4xlarge

r6a.48xlarge pairs 192 vCPUs with 1536GB of RAM at $10.8864/hr On-Demand (about $7838/mo at 24×7). r6a.4xlarge pairs 16 vCPUs with 128GB at $0.9072/hr (~$653/mo). r6a.4xlarge is 92% cheaper per hour than r6a.48xlarge ($9.9792/hr gap).

Because both instances are in the **r6a family**, the only thing that changes between them is sizing — same silicon, same architecture (AMD EPYC (x86_64)), same burstable/sustained behavior. The choice is purely about how much capacity you actually need: r6a.48xlarge gives you 192 vCPUs and 1536GB of RAM, r6a.4xlarge gives you 16 vCPUs and 128GB. 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 pending for r6a.48xlarge and 4078/36366 for r6a.4xlarge. 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 r6a.48xlarge when your workload is closer to memory-optimized (memory-bound work — in-memory databases, real-time analytics, large caches). Pick r6a.4xlarge 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.