Instances›AWS EC2›r5b›r5b.4xlarge
Compute
vCPUs16
Memory128 GiB
Mem / vCPU8.00 GiB
ProcessorXeon Platinum 8259
Clock speed3.1 GHz
Architecturex86_64
Storage
TypeEBS only
Bandwidth10,000 Mbps
Throughput1250 MB/s
IOPS43,333
Networking
PerformanceUp to 10 Gigabit
Max ENIs8
IPv6Yes
GPUNone
Family sizes
r5b.large2 vCPU · 16 GiB
r5b.xlarge4 vCPU · 32 GiB
r5b.2xlarge8 vCPU · 64 GiB
r5b.4xlarge16 vCPU · 128 GiB
r5b.8xlarge32 vCPU · 256 GiB
r5b.12xlarge48 vCPU · 384 GiB
r5b.16xlarge64 vCPU · 512 GiB
r5b.24xlarge96 vCPU · 768 GiB
r5b.metal96 vCPU · 768 GiB
r5b.4xlarge

The r5b.4xlarge pairs 16 vCPU with 128 GiB of RAM, the 8.00 GiB-per-vCPU ratio that marks a memory-optimized instance. In the name, "r" stands for RAM, "5" is the generation, "b" marks block-storage optimisation and "4xlarge" is the size within the r5b family. It runs on Intel Xeon Platinum 8259 (Cascade Lake) at 3.1 GHz, and AWS introduced it in December 2020. AWS has since shipped r6i, r7i, r8i and r9g; r6i.4xlarge is the direct replacement at this size. mh.vs1.2xlarge on Rackspace Spot lines up one-for-one: 16 vCPU and 128 GiB, $1.19/hr on AWS in US East (N. Virginia), from $0.021/hr on Rackspace Spot.

Pricing by region
1 hr
RegionAWS on-demandAWS Spot1-yr Reserved3-yr ReservedRackspace SpotYou save
US East, N. Virginia$1.192$0.473$0.751$0.483$0.021
$1.171 savings
US Central, Chicagono AWS region$0.021
US Central, Dallasno AWS region$0.131
Hong Kong$0.021
Sydney, Australia$1.448$0.531$0.912$0.586$0.021
$1.427 savings
London, UK$1.400$0.462$0.886$0.592$0.131
$1.269 savings
US West, San Jose$0.002
US Central, Dallas 2no AWS region$0.242
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 128 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. r6i.4xlarge is the newer generation at this size.
  • ●The working set needs more than 128 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
  • ●CPU-bound work. You are paying for memory this workload will not use.
r5b.4xlarge runs $870/mo on AWS on-demand. The equivalent on Rackspace Spot: $15/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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