Instances›AWS EC2›c9g›c9g.12xlarge
Compute
vCPUs48
Memory96 GiB
Mem / vCPU2.00 GiB
ProcessorGraviton5 Processor
Clock speed3.3 GHz
Architecturearm64
Storage
TypeEBS only
Bandwidth18,000 Mbps
Throughput2250 MB/s
IOPS72,000
Networking
Performance25 Gigabit
Max ENIs12
IPv6Yes
GPUNone
Family sizes
c9g.medium1 vCPU · 2 GiB
c9g.large2 vCPU · 4 GiB
c9g.xlarge4 vCPU · 8 GiB
c9g.2xlarge8 vCPU · 16 GiB
c9g.4xlarge16 vCPU · 32 GiB
c9g.8xlarge32 vCPU · 64 GiB
c9g.12xlarge48 vCPU · 96 GiB
c9g.16xlarge64 vCPU · 128 GiB
c9g.24xlarge96 vCPU · 192 GiB
c9g.48xlarge192 vCPU · 384 GiB
c9g.metal-48xl192 vCPU · 384 GiB
c9g.12xlarge

c9g.12xlarge is AWS's compute-optimized EC2 size at 48 vCPU and 96 GiB. In the name, "c" stands for compute, "9" is the generation, "g" marks AWS Graviton (ARM) processors and "12xlarge" is the size within the c9g family. It runs on AWS Graviton5 Processor at 3.3 GHz, and AWS introduced it in June 2026. c9g is the current generation of the c family, so there is no newer AWS size to migrate to. The closest Spot shape is ch.vs1.2xlarge at 16 vCPU, so this instance maps to 3 of them — 48 vCPU and 96 GiB across the fleet, about 94% below the US East (N. Virginia) on-demand rate. 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

c9g.12xlarge gives you 48 vCPU and 96 GiB in a single machine. The largest comparable Spot node, ch.vs1.2xlarge, is 16 vCPU and 32 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 96 GiB in one process, it does not.

x86_64 onlyc9g.12xlarge 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$2.087$0.563$0.123
$1.964 savings
US Central, Chicagono AWS region$0.033
US Central, Dallasno AWS region$0.333
Hong Kong$0.123
Sydney, Australia$0.123
London, UK$0.393
US West, San Jose$0.006
US Central, Dallas 2no AWS region$0.366
US East, N. Virginia 2$2.087$0.563$0.486
$1.601 savings
When to use it
Good for
  • ●High-traffic web and API serving
  • ●Scientific modelling and simulation
  • ●Ad serving and real-time bidding
  • ●Workloads that fit inside 96 GiB of RAM
  • ●Parallel work that can occupy 48 vCPU
  • ●Network-heavy services — AWS rates this size at 25 Gigabit
  • ●Anything that shards cleanly across 3 nodes, which is how it maps onto Rackspace Spot
Avoid if
  • ●The working set needs more than 96 GiB of RAM
  • ●You cannot rebuild x86-only binaries or vendor images for aarch64
  • ●GPU or FPGA acceleration is needed
  • ●Memory-hungry applications. A memory-optimized family gives more RAM per dollar.
  • ●More than 2.00 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.
Stop overpaying AWS. This compute costs $1,523/mo on AWS vs $90/mo on Rackspace Spot.
  • 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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