Instances›AWS EC2›r8ib›r8ib.4xlarge
Compute
vCPUs16
Memory128 GiB
Mem / vCPU8.00 GiB
ProcessorXeon Scalable
Clock speed3.9 GHz
Architecturex86_64
Storage
TypeEBS only
Bandwidth25,000 Mbps
Throughput3125 MB/s
IOPS120,000
Networking
PerformanceUp to 33.33 Gigabit
Max ENIs8
IPv6Yes
GPUNone
Family sizes
r8ib.large2 vCPU · 16 GiB
r8ib.xlarge4 vCPU · 32 GiB
r8ib.2xlarge8 vCPU · 64 GiB
r8ib.4xlarge16 vCPU · 128 GiB
r8ib.8xlarge32 vCPU · 256 GiB
r8ib.12xlarge48 vCPU · 384 GiB
r8ib.16xlarge64 vCPU · 512 GiB
r8ib.24xlarge96 vCPU · 768 GiB
r8ib.32xlarge128 vCPU · 1024 GiB
r8ib.48xlarge192 vCPU · 1536 GiB
r8ib.metal-48xl192 vCPU · 1536 GiB
r8ib.96xlarge384 vCPU · 3072 GiB
r8ib.metal-96xl384 vCPU · 3072 GiB
r8ib.4xlarge

r8ib.4xlarge is AWS's memory-optimized EC2 size at 16 vCPU and 128 GiB. In the name, "r" stands for RAM, "8" is the generation, "ib" marks Intel processors and block-storage optimisation and "4xlarge" is the size within the r8ib family. It runs on Intel Xeon Scalable (Granite Rapids) at 3.9 GHz, and AWS introduced it in April 2026. AWS has since shipped r9g; r9g.4xlarge is the direct replacement at this size. On Rackspace Spot the same shape is mh.vs1.2xlarge — 16 vCPU, 128 GiB, matched on both dimensions, $1.67/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$1.674$0.792$0.021
$1.653 savings
US Central, Chicagono AWS region$0.021
US Central, Dallasno AWS region$0.131
Hong Kong$0.021
Sydney, Australia$0.021
London, UK$0.131
US West, San Jose$2.008$0.623$0.002
$2.006 savings
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 33.33 Gigabit
Avoid if
  • ●The working set needs more than 128 GiB of RAM
  • ●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 16 vCPU would sit idle.
  • ●Local NVMe or instance-store disk is a hard requirement
  • ●GPU or FPGA acceleration is needed
r8ib.4xlarge runs $1,222/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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