Instances›AWS EC2›r8g›r8g.16xlarge
Compute
vCPUs64
Memory512 GiB
Mem / vCPU8.00 GiB
ProcessorGraviton4 Processor
Clock speed2.7 GHz
Architecturearm64
Storage
TypeEBS only
Bandwidth20,000 Mbps
Throughput2500 MB/s
IOPS80,000
Networking
Performance30 Gigabit
Max ENIs15
IPv6Yes
GPUNone
Family sizes
r8g.medium1 vCPU · 8 GiB
r8g.large2 vCPU · 16 GiB
r8g.xlarge4 vCPU · 32 GiB
r8g.2xlarge8 vCPU · 64 GiB
r8g.4xlarge16 vCPU · 128 GiB
r8g.8xlarge32 vCPU · 256 GiB
r8g.12xlarge48 vCPU · 384 GiB
r8g.16xlarge64 vCPU · 512 GiB
r8g.24xlarge96 vCPU · 768 GiB
r8g.metal-24xl96 vCPU · 768 GiB
r8g.48xlarge192 vCPU · 1536 GiB
r8g.metal-48xl192 vCPU · 1536 GiB
r8g.16xlarge

The r8g.16xlarge is a memory-optimized AWS EC2 instance: 64 vCPU and 512 GiB of memory, 8.00 GiB per vCPU. In the name, "r" stands for RAM, "8" is the generation, "g" marks AWS Graviton (ARM) processors and "16xlarge" is the size within the r8g family. It runs on AWS Graviton4 Processor at 2.7 GHz, and AWS introduced it in July 2024. AWS has since shipped r9g; r9g.16xlarge is the direct replacement at this size. No single Spot node covers 64 vCPU and 512 GiB, so the equivalent is a fleet: 4 × mh.vs1.2xlarge, 64 vCPU and 512 GiB in total, $3.77/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

r8g.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 onlyr8g.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$3.770$0.566$2.494$1.710$0.084
$3.686 savings
US Central, Chicagono AWS region$0.084
US Central, Dallasno AWS region$0.524
Hong Kong$4.998$3.296$2.245$0.084
$4.914 savings
Sydney, Australia$4.518$1.053$2.986$2.053$0.084
$4.434 savings
London, UK$4.428$0.483$2.936$2.002$0.524
$3.904 savings
US West, San Jose$4.189$0.790$2.771$1.900$0.008
$4.181 savings
US Central, Dallas 2no AWS region$0.968
When to use it
Good for
  • ●Database instances that keep the working set in RAM
  • ●Graph and search workloads with large indexes
  • ●In-memory caches such as Redis and Memcached
  • ●Workloads that fit inside 512 GiB of RAM
  • ●Parallel work that can occupy 64 vCPU
  • ●Network-heavy services — AWS rates this size at 30 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
  • ●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
$2,752/mo on AWS on-demand against $61/mo on Rackspace Spot for the 4-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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