Instances›AWS EC2›r8i-flex›r8i-flex.8xlarge
Compute
vCPUs32
Memory256 GiB
Mem / vCPU8.00 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 ENIs10
IPv6Yes
GPUNone
Family sizes
r8i-flex.large2 vCPU · 16 GiB
r8i-flex.xlarge4 vCPU · 32 GiB
r8i-flex.2xlarge8 vCPU · 64 GiB
r8i-flex.4xlarge16 vCPU · 128 GiB
r8i-flex.8xlarge32 vCPU · 256 GiB
r8i-flex.12xlarge48 vCPU · 384 GiB
r8i-flex.16xlarge64 vCPU · 512 GiB
r8i-flex.8xlarge

The r8i-flex.8xlarge pairs 32 vCPU with 256 GiB of RAM, the 8.00 GiB-per-vCPU ratio that marks a memory-optimized instance. It runs on Intel Xeon Scalable (Granite Rapids) at 3.9 GHz, and AWS introduced it in August 2025. Spot's node ladder tops out below this size, so r8i-flex.8xlarge becomes 2 × mh.vs1.2xlarge (32 vCPU, 256 GiB combined), $2.11/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

r8i-flex.8xlarge gives you 32 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 32 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$2.111$0.868$0.042
$2.070 savings
US Central, Chicagono AWS region$0.042
US Central, Dallasno AWS region$0.262
Hong Kong$0.042
Sydney, Australia$2.531$0.895$0.042
$2.489 savings
London, UK$2.480$0.864$0.262
$2.218 savings
US West, San Jose$2.346$0.311$0.004
$2.342 savings
US Central, Dallas 2no AWS region$0.484
When to use it
Good for
  • ●Graph and search workloads with large indexes
  • ●In-memory caches such as Redis and Memcached
  • ●Large JVM heaps and application servers that hold state
  • ●Workloads that fit inside 256 GiB of RAM
  • ●Parallel work that can occupy 32 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
  • ●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
  • ●The work is single-threaded. Most of these 32 vCPU would sit idle.
  • ●Local NVMe or instance-store disk is a hard requirement
$1,541/mo on AWS on-demand against $31/mo on Rackspace Spot for the 2-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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