The r8gb.4xlarge is a memory-optimized AWS EC2 instance: 16 vCPU and 128 GiB of memory, 8.00 GiB per vCPU. In the name, "r" stands for RAM, "8" is the generation, "gb" marks AWS Graviton (ARM) processors and block-storage optimisation and "4xlarge" is the size within the r8gb family. It runs on AWS Graviton4 Processor at 2.8 GHz, and AWS introduced it in September 2025. AWS has since shipped r9g; r9g.4xlarge is the direct replacement at this size. Rackspace Spot's mh.vs1.2xlarge is a like-for-like substitute at 16 vCPU and 128 GiB, $1.46/hr on AWS in US East (N. Virginia), from $0.021/hr on Rackspace Spot.
| Region | AWS on-demand | AWS Spot | 1-yr Reserved | 3-yr Reserved | Rackspace Spot | You save |
|---|---|---|---|---|---|---|
| US East, N. Virginia | $1.457 | $0.448 | $0.021 | $1.436 savings | ||
| US Central, Chicago | no AWS region | $0.021 | ||||
| US Central, Dallas | no AWS region | $0.131 | ||||
| Hong Kong | $0.021 | |||||
| Sydney, Australia | $0.021 | |||||
| London, UK | $0.131 | |||||
| US West, San Jose | $0.002 | |||||
| US Central, Dallas 2 | no AWS region | $0.242 |