Instances›AWS EC2›c5a›c5a.4xlarge
Compute
vCPUs16
Memory32 GiB
Mem / vCPU2.00 GiB
ProcessorEPYC 7R32
Clock speed3.3 GHz
Architecturex86_64
Storage
TypeEBS only
Bandwidth3,170 Mbps
Throughput396.25 MB/s
IOPS13,300
Networking
PerformanceUp to 10 Gigabit
Max ENIs8
IPv6Yes
GPUNone
Family sizes
c5a.large2 vCPU · 4 GiB
c5a.xlarge4 vCPU · 8 GiB
c5a.2xlarge8 vCPU · 16 GiB
c5a.4xlarge16 vCPU · 32 GiB
c5a.8xlarge32 vCPU · 64 GiB
c5a.12xlarge48 vCPU · 96 GiB
c5a.16xlarge64 vCPU · 128 GiB
c5a.24xlarge96 vCPU · 192 GiB
c5a.4xlarge

The c5a.4xlarge pairs 16 vCPU with 32 GiB of RAM, the 2.00 GiB-per-vCPU ratio that marks a compute-optimized instance. In the name, "c" stands for compute, "5" is the generation, "a" marks AMD processors and "4xlarge" is the size within the c5a family. It runs on AMD EPYC 7R32 at 3.3 GHz, and AWS introduced it in June 2020. AWS has since shipped c6a, c7a, c8a and c9g; c6a.4xlarge is the direct replacement at this size, scoring 332,450 CoreMark/s against this instance's 290,553 — roughly 14% more throughput for the same vCPU count. ch.vs1.2xlarge on Rackspace Spot lines up one-for-one: 16 vCPU and 32 GiB, about 93% 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$0.616$0.259$0.388$0.266$0.041
$0.575 savings
US Central, Chicagono AWS region$0.011
US Central, Dallasno AWS region$0.111
Hong Kong$0.776$0.489$0.335$0.041
$0.735 savings
Sydney, Australia$0.800$0.389$0.504$0.346$0.041
$0.759 savings
London, UK$0.728$0.284$0.459$0.314$0.131
$0.597 savings
US West, San Jose$0.760$0.248$0.479$0.328$0.002
$0.758 savings
US Central, Dallas 2no AWS region$0.122
US East, N. Virginia 2$0.616$0.259$0.388$0.266$0.162
$0.454 savings
When to use it
Good for
  • ●Scientific modelling and simulation
  • ●Ad serving and real-time bidding
  • ●Game servers and matchmaking
  • ●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 10 Gigabit
Avoid if
  • ●Starting a new deployment. c6a.4xlarge is the newer generation at this size.
  • ●The working set needs more than 32 GiB of RAM
  • ●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
  • ●Memory-hungry applications. A memory-optimized family gives more RAM per dollar.
$450/mo on AWS on-demand against $30/mo on Rackspace Spot for the 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.
Build your Cloudspace
Frequently asked questions