Instances›AWS EC2›r8a›r8a.12xlarge
Compute
vCPUs48
Memory384 GiB
Mem / vCPU8.00 GiB
ProcessorEPYC 9R45 Processor
Clock speedUp to 4.5 GHz
Architecturex86_64
Storage
TypeEBS only
Bandwidth15,000 Mbps
Throughput1875 MB/s
IOPS60,000
Networking
Performance22.5 Gigabit
Max ENIs12
IPv6Yes
GPUNone
Family sizes
r8a.medium1 vCPU · 8 GiB
r8a.large2 vCPU · 16 GiB
r8a.xlarge4 vCPU · 32 GiB
r8a.2xlarge8 vCPU · 64 GiB
r8a.4xlarge16 vCPU · 128 GiB
r8a.8xlarge32 vCPU · 256 GiB
r8a.12xlarge48 vCPU · 384 GiB
r8a.16xlarge64 vCPU · 512 GiB
r8a.24xlarge96 vCPU · 768 GiB
r8a.metal-24xl96 vCPU · 768 GiB
r8a.48xlarge192 vCPU · 1536 GiB
r8a.metal-48xl192 vCPU · 1536 GiB
r8a.12xlarge

r8a.12xlarge is AWS's memory-optimized EC2 size at 48 vCPU and 384 GiB. In the name, "r" stands for RAM, "8" is the generation, "a" marks AMD processors and "12xlarge" is the size within the r8a family. It runs on AMD EPYC 9R45 Processor at Up to 4.5 GHz, and AWS introduced it in November 2025. AWS has since shipped r9g; r9g.12xlarge is the direct replacement at this size. The closest Spot shape is mh.vs1.2xlarge at 16 vCPU, so this instance maps to 3 of them — 48 vCPU and 384 GiB across the fleet, $3.83/hr on AWS in US East (N. Virginia), from $0.063/hr on Rackspace Spot. Spot delivers compute as managed Kubernetes, so a node pool of that size is the native shape of the answer rather than a workaround — provided the workload scales horizontally.

Match qualityScale-out match

r8a.12xlarge gives you 48 vCPU and 384 GiB in a single machine. The largest comparable Spot node, mh.vs1.2xlarge, is 16 vCPU and 128 GiB, so the equivalent here is 3 nodes rather than one.

Spot runs as managed Kubernetes, so a 3-node pool is the normal way to run things rather than a workaround. If your workload already sits behind a load balancer, a queue or a scheduler, it spreads across them without changes. If it needs all 48 cores and 384 GiB in one process, it does not.

Pricing by region
1 hr
RegionAWS on-demandAWS Spot1-yr Reserved3-yr ReservedRackspace SpotYou save
US East, N. Virginia$3.834$1.054$0.063
$3.771 savings
US Central, Chicagono AWS region$0.063
US Central, Dallasno AWS region$0.393
Hong Kong$0.063
Sydney, Australia$0.063
London, UK$0.393
US West, San Jose$0.006
US Central, Dallas 2no AWS region$0.726
When to use it
Good for
  • ●OLAP and business intelligence query engines
  • ●Real-time analytics over hot datasets
  • ●Database instances that keep the working set in RAM
  • ●Workloads that fit inside 384 GiB of RAM
  • ●Parallel work that can occupy 48 vCPU
  • ●Network-heavy services — AWS rates this size at 22.5 Gigabit
  • ●Anything that shards cleanly across 3 nodes, which is how it maps onto Rackspace Spot
Avoid if
  • ●The working set needs more than 384 GiB of RAM
  • ●Local NVMe or instance-store disk is a hard requirement
  • ●GPU or FPGA acceleration is needed
  • ●CPU-bound work. You are paying for memory this workload will not use.
  • ●More than 8.00 GiB of RAM per vCPU is needed — that ratio is fixed for the whole family
  • ●The work is single-threaded. Most of these 48 vCPU would sit idle.
$2,799/mo on AWS on-demand against $46/mo on Rackspace Spot for the 3-node equivalent — market-priced, not list-priced.
  • Spot sells spare capacity at market prices. It is the cheapest compute on the internet.
  • Prices are set by supply and demand. You pay what the market decides.
  • Compute is delivered as fully managed Kubernetes. All infrastructure is taken care of.
  • Egress costs $0.01/GB after the free allowance. AWS charges $0.09/GB.
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