db.r8a.4xlargevsdb.r8g.4xlarge
db.r8g.4xlarge is 21% cheaper than db.r8a.4xlarge on demand in US East (N. Virginia), saving $367.34 a month. Per vCPU, db.r8g.4xlarge costs 60% less. They use different processor architectures (x86_64 and arm64), so software built for one may need rebuilding to run on the other.
| At a glance | db.r8a.4xlarge | db.r8g.4xlarge |
|---|---|---|
| On-demand | $2.415/hr | $1.912/hr21% less |
| Lowest rate | $1.932/hr1-yr savings plan, hourly commitment | $1.53/hr21% less1-yr savings plan, hourly commitment |
| Size | 8 vCPUs, 128 GiB | 16 vCPUs, 128 GiB |
| Processor | 5th Generation AMD EPYC | AWS Graviton4 |
| Architecture | x86_64 | arm64 |
Prices in US East (N. Virginia)
“Off” is the discount against each type’s own on-demand price. PostgreSQL, USD per hour.
| Option | db.r8a.4xlarge | db.r8g.4xlarge | db.r8g.4xlarge vs db.r8a.4xlarge |
|---|---|---|---|
| On-demandPay by the hour | $2.415 | $1.912 | ▼ 21% |
| 1-yr reservedNo upfront | — | 33% off$1.281 | — |
| 3-yr reservedNo upfront | — | 53% off$0.8986 | — |
| 1-yr savings planHourly commitment | 20% off$1.932 | 20% off$1.53 | ▼ 21% |
Key differences
The biggest lead each one has.
Where db.r8a.4xlarge leads
Sustained clock4.5 GHz vs 2.8 GHz
61% higherWhere db.r8g.4xlarge leads
On-demand price$1.912 vs $2.415 per hour
21% cheapervCPUs16 vs 8
2× higherSpecs
10 of 24 specs differ. Those are in bold.
| Compute5 of 8 differ | db.r8a.4xlarge | db.r8g.4xlarge |
|---|---|---|
| vCPUs | 8 | 16 |
| Physical cores | 16 | 16 |
| Threads per core | 1 | 1 |
| Architecture | x86_64 | arm64 |
| Processor | 5th Generation AMD EPYC | AWS Graviton4 |
| CPU maker | AMD | AWS |
| Sustained clock | 4.5 GHz | 2.8 GHz |
| Burstable | No | No |
| MemoryAll 1 match | db.r8a.4xlarge | db.r8g.4xlarge |
|---|---|---|
| Memory (GiB) | 128 | 128 |
| Networking1 of 3 differ | db.r8a.4xlarge | db.r8g.4xlarge |
|---|---|---|
| Network | Up to 15000 Mbps | Up to 15 Gigabit |
| Network baseline | 7.5 Gbps | 7.5 Gbps |
| Network peak | 15 Gbps | 15 Gbps |
| Storage1 of 7 differ | db.r8a.4xlarge | db.r8g.4xlarge |
|---|---|---|
| Storage | EBS Only | Aurora IO Optimization Mode |
| EBS baseline bandwidth | 5,000 Mbps | 5,000 Mbps |
| EBS max bandwidth | 10,000 Mbps | 10,000 Mbps |
| EBS baseline throughput | 625 MB/s | 625 MB/s |
| EBS max throughput | 1,250 MB/s | 1,250 MB/s |
| EBS baseline IOPS | 20,000 | 20,000 |
| EBS max IOPS | 40,000 | 40,000 |
| Instance details2 of 4 differ | db.r8a.4xlarge | db.r8g.4xlarge |
|---|---|---|
| Family | r8a | r8g |
| Category | Memory optimized | Memory optimized |
| Current generation | Yes | Yes |
| Normalization factor | – | 41.6 |
| Other1 of 1 differ | db.r8a.4xlarge | db.r8g.4xlarge |
|---|---|---|
| Hardware Basis | r8a.4xlarge | r8g.4xlarge |
On-demand prices by region
Cheapest for db.r8a.4xlarge first. PostgreSQL, USD per hour.
| Region | db.r8a.4xlarge | db.r8g.4xlarge | Difference |
|---|---|---|---|
| US East (N. Virginia)Used in summaryus-east-1 | $2.415 | $1.912 | ▼ 21% |
| US East (Ohio)us-east-2 | $2.415 | $1.912 | ▼ 21% |
| US West (Oregon)us-west-2 | $2.415 | $1.912 | ▼ 21% |
| Canada (Central)ca-central-1 | $2.608 | $2.066 | ▼ 21% |
| EU (Ireland)eu-west-1 | $2.705 | $2.144 | ▼ 21% |
| Europe (Spain)eu-south-2 | $2.705 | $2.144 | ▼ 21% |
| Asia Pacific (Tokyo)ap-northeast-1 | $2.898 | $2.296 | ▼ 21% |
| EU (Frankfurt)eu-central-1 | $2.946 | $2.328 | ▼ 21% |
Keep exploring
Each type’s own page, and how it compares with others.
db.r8a.4xlarge
db.r8a.4xlarge prices and specsEvery size in the r8a familyCompare db.r8a.4xlarge with
db.r8g.4xlarge
db.r8g.4xlarge prices and specsEvery size in the r8g familyCompare db.r8g.4xlarge with
AWS RDS PostgreSQL prices in USD. Monthly figures use 730 hours. Prices last updated 12 Nov 2026.