Amazon Elastic Compute Cloud
User Guide for Linux Instances

Memory Optimized Instances

Memory optimized instances are designed to deliver fast performance for workloads that process large data sets in memory.

R4 Instances

R4 instances are well suited for the following applications:

  • High performance relational (MySQL) and NoSQL (MongoDB, Cassandra) databases.

  • Distributed web scale cache stores that provide in-memory caching of key-value type data (Memcached and Redis).

  • In-memory databases using optimized data storage formats and analytics for business intelligence (for example, SAP HANA).

  • Applications performing real-time processing of big unstructured data (financial services, Hadoop/Spark clusters).

  • High-performance computing (HPC) and Electronic Design Automation (EDA) applications.

X1 Instances

X1 instances are well suited for the following applications:

  • In-memory databases such SAP HANA, including SAP-certified support for Business Suite S/4HANA, Business Suite on HANA (SoH), Business Warehouse on HANA (BW), and Data Mart Solutions on HANA. For more information, see SAP HANA on the AWS Cloud.

  • Big-data processing engines such as Apache Spark or Presto.

  • High-performance computing (HPC) applications.

R3 Instances

R3 instances are well suited for the following applications:

  • High performance relational (MySQL) and NoSQL (MongoDB, Cassandra) databases.

  • In-memory analytics.

  • Genome assembly and analysis.

  • Enterprise applications (for example, Microsoft SharePoint).

Hardware Specifications

For more information about the hardware specifications for each Amazon EC2 instance type, see Amazon EC2 Instance Types.

Memory Performance

R4 instances enable up to 488 GiB of RAM.

X1 instances include Intel Scalable M​​emory Buffers, providing 300 GiB/s of sustainable memory-read bandwidth and 140 GiB/s of sustainable memory-write bandwidth.

R3 instances enable up to 244 GiB of RAM.

Memory optimized instances have high-memory and require 64-bit HVM AMIs to take advantage of that capacity. HVM AMIs provide superior performance in comparison to paravirtual (PV) AMIs on high-memory instance types. For more information, see Linux AMI Virtualization Types.

Compute Performance

R4 instances feature up to 64 vCPUs and are powered by two AWS-customized Intel XEON processors based on E5-2686v4 that feature high-memory bandwidth and larger L3 caches to boost the performance of in-memory applications.

X1 instances feature up to 128 vCPUs and are powered by four Intel Xeon E7-8880 v3 processors that feature high-memory bandwidth and larger L3 caches to boost the performance of in-memory applications.

Memory optimized instances enable increased cryptographic performance through the latest Intel AES-NI feature, support Intel Transactional Synchronization Extensions (TSX) to boost the performance of in-memory transactional data processing, and support Advanced Vector Extensions 2 (Intel AVX2) processor instructions to expand most integer commands to 256 bits.

Some memory optimized instances provide the ability to control processor C-states and P-states on Linux. C-states control the sleep levels that a core can enter when it is inactive, while P-states control the desired performance (measured by CPU frequency) from a core. For more information, see Processor State Control for Your EC2 Instance.

Network Performance

To increase network performance of your memory optimized instances, enable enhanced networking. For more information, see Enhanced Networking on Linux.

X1 and R4 instances deliver high packet per second performance with consistently low latencies using Elastic Network Adapter (ENA). Most applications do not consistently need a high level of network performance, but can benefit from having access to increased bandwidth when they send or receive data. The smaller R4 instance sizes offer peak throughput of 10 Gbps. These instances use a network I/O credit mechanism to allocate network bandwidth to instances based on average bandwidth utilization. These instances accrue credits when their network throughput is below their baseline limits, and can use these credits when they perform network data transfers. For workloads that require access to 10 Gbps of bandwidth on a sustained basis, we recommend using r4.8xlarge and x1.16xlarge instances, which can utilize up to 10 Gbps of network bandwidth. The r4.16xlarge, x1.32xlarge, and x1e.32xlarge instances can utilize up to 25 Gbps of network bandwidth.

Instance Features

The following is a summary of features for memory optimized instances.

VPC only EBS only SSD volumes Placement group Enhanced networking




Intel 82599 VF






X1 Yes Yes Yes ENA

For more information, see the following:

Support for vCPUs

Memory optimized instances provide a high number of vCPUs, which can cause launch issues with operating systems that have a lower vCPU limit. We strongly recommend that you use the latest AMIs when you launch memory optimized instances.

The following AMIs support launching memory optimized instances:

  • Amazon Linux AMI 2016.03 (HVM) or later

  • Ubuntu Server 14.04 LTS (HVM)

  • Red Hat Enterprise Linux 7.1 (HVM)

  • SUSE Linux Enterprise Server 12 SP1 (HVM)

  • Windows Server 2016

  • Windows Server 2012 R2

  • Windows Server 2012

  • Windows Server 2008 R2 64-bit

  • Windows Server 2008 SP2 64-bit

Instance Limits

  • You can't launch X1 instances using a Windows Server 2008 SP2 64-bit AMI, except for x1.16xlarge instances.

  • With earlier versions of the Windows Server 2008 R2 64-bit AMI, you can't launch r4.large and r4.4xlarge instances. If you experience this issue, update to the latest version of this AMI.

  • There is a limit on the total number of instances that you can launch in a region, and there are additional limits on some instance types. For more information, see How many instances can I run in Amazon EC2?. To request a limit increase, use the Amazon EC2 Instance Request Form.