Instances›AWS EC2›r8gb›r8gb.16xlarge
Compute
vCPUs64
Memory512 GiB
Mem / vCPU8.00 GiB
ProcessorGraviton4 Processor
Clock speed2.8 GHz
Architecturearm64
Storage
TypeEBS only
Bandwidth100,000 Mbps
Throughput12500 MB/s
IOPS480,000
Networking
Performance133.33 Gigabit
Max ENIs16
IPv6Yes
GPUNone
Family sizes
r8gb.medium1 vCPU · 8 GiB
r8gb.large2 vCPU · 16 GiB
r8gb.xlarge4 vCPU · 32 GiB
r8gb.2xlarge8 vCPU · 64 GiB
r8gb.4xlarge16 vCPU · 128 GiB
r8gb.8xlarge32 vCPU · 256 GiB
r8gb.12xlarge48 vCPU · 384 GiB
r8gb.16xlarge64 vCPU · 512 GiB
r8gb.24xlarge96 vCPU · 768 GiB
r8gb.metal-24xl96 vCPU · 768 GiB
r8gb.48xlarge192 vCPU · 1536 GiB
r8gb.metal-48xl192 vCPU · 1536 GiB
r8gb.16xlarge

r8gb.16xlarge is AWS's memory-optimized EC2 size at 64 vCPU and 512 GiB. In the name, "r" stands for RAM, "8" is the generation, "gb" marks AWS Graviton (ARM) processors and block-storage optimisation and "16xlarge" 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.16xlarge is the direct replacement at this size. The closest Spot shape is mh.vs1.2xlarge at 16 vCPU, so this instance maps to 4 of them — 64 vCPU and 512 GiB across the fleet, $5.83/hr on AWS in US East (N. Virginia), from $0.084/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

r8gb.16xlarge gives you 64 vCPU and 512 GiB in a single machine. The largest comparable Spot node, mh.vs1.2xlarge, is 16 vCPU and 128 GiB, so the equivalent here is 4 nodes rather than one.

Spot runs as managed Kubernetes, so a 4-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 64 cores and 512 GiB in one process, it does not.

x86_64 onlyr8gb.16xlarge is Graviton (arm64) and Rackspace Spot has no arm64 nodes, so you'd be moving to x86. You'll need x86 builds of your images, and per-core speed differs between the chips — worth testing before you decide how many nodes to run.
Pricing by region
1 hr
RegionAWS on-demandAWS Spot1-yr Reserved3-yr ReservedRackspace SpotYou save
US East, N. Virginia$5.830$1.141$0.084
$5.746 savings
US Central, Chicagono AWS region$0.084
US Central, Dallasno AWS region$0.524
Hong Kong$0.084
Sydney, Australia$0.084
London, UK$0.524
US West, San Jose$0.008
US Central, Dallas 2no AWS region$0.968
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 512 GiB of RAM
  • ●Parallel work that can occupy 64 vCPU
  • ●Network-heavy services — AWS rates this size at 133.33 Gigabit
  • ●Anything that shards cleanly across 4 nodes, which is how it maps onto Rackspace Spot
Avoid if
  • ●The working set needs more than 512 GiB of RAM
  • ●You cannot rebuild x86-only binaries or vendor images for aarch64
  • ●The work is single-threaded. Most of these 64 vCPU would sit idle.
  • ●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.
r8gb.16xlarge runs $4,256/mo on AWS on-demand. The 4-node equivalent on Rackspace Spot: $61/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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