Instances›AWS EC2›r8idn›r8idn.12xlarge
Compute
vCPUs48
Memory384 GiB
Mem / vCPU8.00 GiB
ProcessorXeon Scalable
Clock speed3.9 GHz
Architecturex86_64
Storage
Type1 × 2,850 GB NVMe SSD
Bandwidth15,000 Mbps
Throughput1875 MB/s
IOPS60,000
Networking
Performance75 Gigabit
Max ENIs12
IPv6Yes
GPUNone
Family sizes
r8idn.large2 vCPU · 16 GiB
r8idn.xlarge4 vCPU · 32 GiB
r8idn.2xlarge8 vCPU · 64 GiB
r8idn.4xlarge16 vCPU · 128 GiB
r8idn.8xlarge32 vCPU · 256 GiB
r8idn.12xlarge48 vCPU · 384 GiB
r8idn.16xlarge64 vCPU · 512 GiB
r8idn.24xlarge96 vCPU · 768 GiB
r8idn.32xlarge128 vCPU · 1024 GiB
r8idn.48xlarge192 vCPU · 1536 GiB
r8idn.metal-48xl192 vCPU · 1536 GiB
r8idn.96xlarge384 vCPU · 3072 GiB
r8idn.metal-96xl384 vCPU · 3072 GiB
r8idn.12xlarge

r8idn.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, "idn" marks Intel processors, local NVMe storage and enhanced networking and "12xlarge" is the size within the r8idn family. It runs on Intel Xeon Scalable (Granite Rapids) at 3.9 GHz, and AWS introduced it in May 2026. 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, $5.63/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

r8idn.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.

No local diskr8idn.12xlarge comes with 1 × 2,850 GB NVMe SSD attached to the machine. Spot nodes use network storage only, so that disk doesn't come with it. If you were using it as fast scratch space, you'd move to a persistent volume or object storage, which are slower to read.
Pricing by region
1 hr
RegionAWS on-demandAWS Spot1-yr Reserved3-yr ReservedRackspace SpotYou save
US East, N. Virginia$5.627$2.544$0.063
$5.564 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
  • ●In-memory caches such as Redis and Memcached
  • ●Large JVM heaps and application servers that hold state
  • ●OLAP and business intelligence query engines
  • ●Workloads that fit inside 384 GiB of RAM
  • ●Jobs that want 1 × 2,850 GB of local NVMe scratch space
  • ●Network-heavy services — AWS rates this size at 75 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
  • ●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.
  • ●GPU or FPGA acceleration is needed
  • ●CPU-bound work. You are paying for memory this workload will not use.
r8idn.12xlarge runs $4,108/mo on AWS on-demand. The 3-node equivalent on Rackspace Spot: $46/mo.
  • 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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