AWS r8id.32xlargevsAWS r8idb.4xlarge

r8id.32xlarge pairs 128 vCPUs with 1024GB of RAM at $10.6445/hr On-Demand (about $7664/mo at 24×7). r8idb.4xlarge pairs 16 vCPUs with 128GB at $1.8758/hr (~$1351/mo). r8idb.4xlarge is 82% cheaper per hour than r8id.32xlarge ($8.7687/hr gap).

Both are generation-8 memory-optimized instances, but they run on different silicon: **r8id.32xlarge** is Intel Xeon (x86_64), **r8idb.4xlarge** is Intel Xeon (x86_64). AMD variants (suffix `a`) are typically 10% cheaper than Intel siblings at comparable single-thread performance. Graviton variants (suffix `g`) are usually 20–40% cheaper but require ARM64-compatible binaries — most modern Linux stacks are fine, but verify any compiled extensions, native modules, or third-party binaries before migrating. Same vCPU/RAM ratio, same network performance class, different processor.

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 r8id.32xlarge and 3359/28236 for r8idb.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 r8id.32xlarge when your workload is closer to memory-optimized (memory-bound work — in-memory databases, real-time analytics, large caches). Pick r8idb.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.