Silicon Triangle
AWS R7 Generation: R7i vs R7a vs R7g
8:1 memory-to-vCPU ratio for in-memory caches, Redis, and transactional databases
Memory-optimized instances are often the most expensive component of an AWS bill. Compare DDR5 memory bandwidth, latency, and cost per gigabyte across Intel, AMD, and Graviton3.
1. Architectural & Silicon Specs Head-to-Head
Comparing underlying processor microarchitectures, memory ratios, and Nitro generation features using representative xlarge sizing.
r7ix86_64
R7I Memory Optimized
ProcessorIntel Xeon Scalable (Sapphire Rapids)
Clock Speed3.2 GHz
RAM / vCPU8.0 GiB/vCPU
Max Network50 Gbps
Max EBS IOPS240,000
AWS NitroSupported
Min Rate (r7i.xlarge)$0.2646/hr
Monthly Est.$193.16/mo
Cost per vCPU$0.0662/hr
Cost per GiB RAM$0.0083/hr
CoreMark Benchmark95,166
CoreMark / $359,660
Price Index87% of highest
Save 13% vs most expensive
Compute / $ Value53% of leader
r7ax86_64
R7A Memory Optimized
ProcessorAMD EPYC 9R14 Processor
Clock SpeedUp to 3.7 GHz
RAM / vCPU8.0 GiB/vCPU
Max Network50 Gbps
Max EBS IOPS240,000
AWS NitroSupported
Min Rate (r7a.xlarge)$0.3043/hr
Monthly Est.$222.14/mo
Cost per vCPU$0.0761/hr
Cost per GiB RAM$0.0095/hr
CoreMark Benchmark136,893
CoreMark / $449,862
Price Index100% of highest
Compute / $ Value66% of leader
r7gARM64 (Graviton)
R7G Memory Optimized
ProcessorAWS Graviton3 Processor
Clock Speed2.5 GHz
RAM / vCPU8.0 GiB/vCPU
Max Network30 Gbps
Max EBS IOPS80,000
AWS NitroSupported
Min Rate (r7g.xlarge)$0.1502/hr
Monthly Est.$109.65/mo
Cost per vCPU$0.0376/hr
Cost per GiB RAM$0.0047/hr
CoreMark Benchmark102,571
CoreMark / $682,896
Price IndexLowest Cost
Save 51% vs most expensive
Compute / $ Value100% (Leader)
2. Side-by-Side Sizing & Pricing Matrix
Direct price and benchmark comparison across matching instance tiers in the lowest-cost region. Lowest hourly cost in each row is highlighted in green.
| Size Tier | vCPU | Memory | r7iLinux Rate | r7aLinux Rate | r7gLinux Rate |
|---|---|---|---|---|---|
| .medium | 1 | 8 GB | — | ||
| .large | 2 | 16 GB | |||
| .xlarge | 4 | 32 GB | |||
| .2xlarge | 8 | 64 GB | |||
| .4xlarge | 16 | 128 GB | |||
| .8xlarge | 32 | 256 GB | |||
| .12xlarge | 48 | 384 GB | |||
| .16xlarge | 64 | 512 GB | |||
| .24xlarge | 96 | 768 GB | — | ||
| .32xlarge | 128 | 1,024 GB | — | — | |
| .48xlarge | 192 | 1,536 GB | — |
3. Workload Decision Framework
Clear, actionable rules on when each family wins based on workload profile, runtime language, and licensing boundaries.
Recommended:R7g (Graviton3)
When: Self-hosted Redis, Valkey, Memcached, or PostgreSQL on Linux
Why: 20% lower cost per gigabyte of RAM with DDR5 memory bandwidth.
Recommended:R7a (AMD Genoa)
When: Large-scale analytical databases or high-throughput OLTP on x86_64
Why: Up to 3.7 GHz clock boost with high memory bus saturation on multi-threaded queries.
Recommended:R7i (Intel)
When: Enterprise Microsoft SQL Server or SAP HANA workloads licensed per-core
Why: High per-core memory capacity helps minimize core-based software license fees.
5. Related Architecture Comparisons
Explore adjacent generational comparisons and silicon trade-offs.