Instances›AWS EC2›c8i-flex›c8i-flex.4xlarge
Compute
vCPUs16
Memory32 GiB
Mem / vCPU2.00 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
c8i-flex.large2 vCPU · 4 GiB
c8i-flex.xlarge4 vCPU · 8 GiB
c8i-flex.2xlarge8 vCPU · 16 GiB
c8i-flex.4xlarge16 vCPU · 32 GiB
c8i-flex.8xlarge32 vCPU · 64 GiB
c8i-flex.12xlarge48 vCPU · 96 GiB
c8i-flex.16xlarge64 vCPU · 128 GiB
c8i-flex.4xlarge

The c8i-flex.4xlarge is a compute-optimized AWS EC2 instance: 16 vCPU and 32 GiB of memory, 2.00 GiB per vCPU. It runs on Intel Xeon Scalable (Granite Rapids) at 3.9 GHz, and AWS introduced it in October 2025. Rackspace Spot's ch.vs1.2xlarge is a like-for-like substitute at 16 vCPU and 32 GiB, about 94% below the US East (N. Virginia) on-demand rate.

Pricing by region
1 hr
RegionAWS on-demandAWS Spot1-yr Reserved3-yr ReservedRackspace SpotYou save
US East, N. Virginia$0.712$0.270$0.041
$0.671 savings
US Central, Chicagono AWS region$0.011
US Central, Dallasno AWS region$0.111
Hong Kong$0.041
Sydney, Australia$0.930$0.317$0.041
$0.889 savings
London, UK$0.846$0.289$0.131
$0.715 savings
US West, San Jose$0.888$0.248$0.002
$0.886 savings
US Central, Dallas 2no AWS region$0.122
US East, N. Virginia 2$0.712$0.270$0.162
$0.550 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 32 GiB of RAM
  • ●Parallel work that can occupy 16 vCPU
  • ●Network-heavy services — AWS rates this size at Up to 15 Gigabit
Avoid if
  • ●The working set needs more than 32 GiB of RAM
  • ●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 16 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 $520/mo on AWS vs $30/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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Frequently asked questions