Instances›AWS EC2›x8g›x8g.4xlarge
Compute
vCPUs16
Memory256 GiB
Mem / vCPU16.00 GiB
ProcessorGraviton4 Processor
Clock speed2.7 GHz
Architecturearm64
Storage
TypeEBS only
Bandwidth10,000 Mbps
Throughput1250 MB/s
IOPS40,000
Networking
PerformanceUp to 15 Gigabit
Max ENIs8
IPv6Yes
GPUNone
Family sizes
x8g.medium1 vCPU · 16 GiB
x8g.large2 vCPU · 32 GiB
x8g.xlarge4 vCPU · 64 GiB
x8g.2xlarge8 vCPU · 128 GiB
x8g.4xlarge16 vCPU · 256 GiB
x8g.8xlarge32 vCPU · 512 GiB
x8g.12xlarge48 vCPU · 768 GiB
x8g.16xlarge64 vCPU · 1024 GiB
x8g.24xlarge96 vCPU · 1536 GiB
x8g.metal-24xl96 vCPU · 1536 GiB
x8g.48xlarge192 vCPU · 3072 GiB
x8g.metal-48xl192 vCPU · 3072 GiB
x8g.4xlarge

x8g.4xlarge is AWS's memory-optimized EC2 size at 16 vCPU and 256 GiB. In the name, "x" is the extra-memory line, "8" is the generation, "g" marks AWS Graviton (ARM) processors and "4xlarge" is the size within the x8g family. It runs on AWS Graviton4 Processor at 2.7 GHz, and AWS introduced it in September 2024. x8g is the current generation of the x family, so there is no newer AWS size to migrate to. The closest Spot shape is mh.vs1.2xlarge at 16 vCPU, so this instance maps to 2 of them — 32 vCPU and 256 GiB across the fleet, $1.56/hr on AWS in US East (N. Virginia), from $0.042/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

x8g.4xlarge gives you 16 vCPU and 256 GiB in a single machine. The largest comparable Spot node, mh.vs1.2xlarge, is 16 vCPU and 128 GiB, so the equivalent here is 2 nodes rather than one.

Spot runs as managed Kubernetes, so a 2-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 16 cores and 256 GiB in one process, it does not.

x86_64 onlyx8g.4xlarge 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$1.563$0.930$0.963$0.534$0.042
$1.521 savings
US Central, Chicagono AWS region$0.042
US Central, Dallasno AWS region$0.262
Hong Kong$0.042
Sydney, Australia$1.876$0.388$1.156$0.641$0.042
$1.834 savings
London, UK$0.262
US West, San Jose$0.004
US Central, Dallas 2no AWS region$0.484
When to use it
Good for
  • ●Large JVM heaps and application servers that hold state
  • ●OLAP and business intelligence query engines
  • ●Real-time analytics over hot datasets
  • ●Workloads that fit inside 256 GiB of RAM
  • ●Parallel work that can occupy 16 vCPU
  • ●Network-heavy services — AWS rates this size at Up to 15 Gigabit
  • ●Anything that shards cleanly across 2 nodes, which is how it maps onto Rackspace Spot
Avoid if
  • ●The working set needs more than 256 GiB of RAM
  • ●You cannot rebuild x86-only binaries or vendor images for aarch64
  • ●More than 16.00 GiB of RAM per vCPU is needed — that ratio is fixed for the whole family
  • ●The work is single-threaded. Most of these 16 vCPU would sit idle.
  • ●Local NVMe or instance-store disk is a hard requirement
  • ●GPU or FPGA acceleration is needed
x8g.4xlarge runs $1,141/mo on AWS on-demand. The 2-node equivalent on Rackspace Spot: $31/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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