Instances›AWS EC2›c6gn›c6gn.16xlarge
Compute
vCPUs64
Memory128 GiB
Mem / vCPU2.00 GiB
ProcessorGraviton2 Processor
Clock speed2.5 GHz
Architecturearm64
Storage
TypeEBS only
Bandwidth38,000 Mbps
Throughput4750 MB/s
IOPS160,000
Networking
Performance100 Gigabit
Max ENIs15
IPv6Yes
GPUNone
Family sizes
c6gn.medium1 vCPU · 2 GiB
c6gn.large2 vCPU · 4 GiB
c6gn.xlarge4 vCPU · 8 GiB
c6gn.2xlarge8 vCPU · 16 GiB
c6gn.4xlarge16 vCPU · 32 GiB
c6gn.8xlarge32 vCPU · 64 GiB
c6gn.12xlarge48 vCPU · 96 GiB
c6gn.16xlarge64 vCPU · 128 GiB
c6gn.metal64 vCPU · 128 GiB
c6gn.16xlarge

The c6gn.16xlarge pairs 64 vCPU with 128 GiB of RAM, the 2.00 GiB-per-vCPU ratio that marks a compute-optimized instance. In the name, "c" stands for compute, "6" is the generation, "gn" marks AWS Graviton (ARM) processors and enhanced networking and "16xlarge" is the size within the c6gn family. It runs on AWS Graviton2 Processor at 2.5 GHz, and AWS introduced it in December 2020. AWS has since shipped c7gn, c8gn and c9g; c7gn.16xlarge is the direct replacement at this size. Spot's node ladder tops out below this size, so c6gn.16xlarge becomes 4 × ch.vs1.2xlarge (64 vCPU, 128 GiB combined), 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

c6gn.16xlarge gives you 64 vCPU and 128 GiB in a single machine. The largest comparable Spot node, ch.vs1.2xlarge, is 16 vCPU and 32 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 128 GiB in one process, it does not.

x86_64 onlyc6gn.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$2.765$0.695$1.745$1.187$0.164
$2.601 savings
US Central, Chicagono AWS region$0.044
US Central, Dallasno AWS region$0.444
Hong Kong$3.664$2.302$1.693$0.164
$3.500 savings
Sydney, Australia$3.616$0.768$2.285$1.676$0.164
$3.452 savings
London, UK$3.280$0.346$2.066$1.642$0.524
$2.756 savings
US West, San Jose$3.456$0.512$2.184$1.642$0.008
$3.448 savings
US Central, Dallas 2no AWS region$0.488
US East, N. Virginia 2$2.765$0.695$1.745$1.187$0.648
$2.117 savings
When to use it
Good for
  • ●Batch processing and CI/CD runners
  • ●Video encoding and transcoding
  • ●High-traffic web and API serving
  • ●Workloads that fit inside 128 GiB of RAM
  • ●Parallel work that can occupy 64 vCPU
  • ●Network-heavy services — AWS rates this size at 100 Gigabit
  • ●Anything that shards cleanly across 4 nodes, which is how it maps onto Rackspace Spot
Avoid if
  • ●Starting a new deployment. c7gn.16xlarge is the newer generation at this size.
  • ●The working set needs more than 128 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
Stop overpaying AWS. This compute costs $2,018/mo on AWS vs $120/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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