Instances›AWS EC2›x8i›x8i.4xlarge
Compute
vCPUs16
Memory256 GiB
Mem / vCPU16.00 GiB
ProcessorXeon Scalable
Clock speed3.9 GHz
Architecturex86_64
Storage
TypeEBS only
Bandwidth10,000 Mbps
Throughput1250 MB/s
IOPS40,000
Networking
PerformanceUp to 15 Gigabit
Max ENIs8
IPv6Yes
GPUNone
Family sizes
x8i.large2 vCPU · 32 GiB
x8i.xlarge4 vCPU · 64 GiB
x8i.2xlarge8 vCPU · 128 GiB
x8i.4xlarge16 vCPU · 256 GiB
x8i.8xlarge32 vCPU · 512 GiB
x8i.12xlarge48 vCPU · 768 GiB
x8i.16xlarge64 vCPU · 1024 GiB
x8i.24xlarge96 vCPU · 1536 GiB
x8i.32xlarge128 vCPU · 2048 GiB
x8i.48xlarge192 vCPU · 3072 GiB
x8i.metal-48xl192 vCPU · 3072 GiB
x8i.64xlarge256 vCPU · 4096 GiB
x8i.96xlarge384 vCPU · 6144 GiB
x8i.metal-96xl384 vCPU · 6144 GiB
x8i.4xlarge

The x8i.4xlarge is a memory-optimized AWS EC2 instance: 16 vCPU and 256 GiB of memory, 16.00 GiB per vCPU. In the name, "x" is the extra-memory line, "8" is the generation, "i" marks Intel processors and "4xlarge" is the size within the x8i family. It runs on Intel Xeon Scalable (Granite Rapids) at 3.9 GHz, and AWS introduced it in January 2026. x8i is the current generation of the x family, so there is no newer AWS size to migrate to. No single Spot node covers 16 vCPU and 256 GiB, so the equivalent is a fleet: 2 × mh.vs1.2xlarge, 32 vCPU and 256 GiB in total, $1.75/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

x8i.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.

Pricing by region
1 hr
RegionAWS on-demandAWS Spot1-yr Reserved3-yr ReservedRackspace SpotYou save
US East, N. Virginia$1.751$0.428$0.042
$1.709 savings
US Central, Chicagono AWS region$0.042
US Central, Dallasno AWS region$0.262
Hong Kong$0.042
Sydney, Australia$2.538$0.804$0.042
$2.497 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
  • ●In-memory caches such as Redis and Memcached
  • ●Large JVM heaps and application servers that hold state
  • ●OLAP and business intelligence query engines
  • ●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
  • ●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 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.
x8i.4xlarge runs $1,278/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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