Amazon Elastic Compute Cloud
User Guide for Linux Instances

Compute Optimized Instances

Compute optimized instances are ideal for compute-bound applications that benefit from high performance processors. They are well suited for the following applications:

  • Batch processing workloads

  • Media transcoding

  • High performance web servers

  • High performance computing (HPC)

  • Scientific modeling

  • Massively multiplayer online (MMO) gaming servers and ad serving engines

  • Machine learning inference and other compute-intensive applications

Hardware Specifications

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

Compute Instance Performance

EBS-optimized instances enable you to get consistently high performance for your EBS volumes by eliminating contention between Amazon EBS I/O and other network traffic from your instance. C4 and C5 instances are EBS-optimized by default at no additional cost. You can enable EBS optimization for your C3 instances for an additional low, hourly fee. For more information, see Amazon EBS–Optimized Instances.

You can enable enhanced networking capabilities. Enhanced networking provides significantly higher packet per second (PPS) performance, lower network jitter, and lower latencies. For more information, see Enhanced Networking on Linux.

The c4.8xlarge instance type provides the ability to control processor C-states and P-states on Linux. The c5.9xlarge and c5.18xlarge instance types provide the ability to control processor C-states. C-states control the sleep levels that a core can enter when it is inactive, while P-states control the desired performance (in CPU frequency) from a core. For more information, see Processor State Control for Your EC2 Instance.

Network Performance

C5 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 c5.4xlarge and smaller instances 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 c5.9xlarge instances, which can utilize up to 10 Gbps of network bandwidth. The c5.18xlarge instances can utilize up to 25 Gbps of network bandwidth.

Compute Instance Features

The following is a summary of features for compute optimized instances:

VPC only EBS only SSD volumes Placement group HVM only Enhanced networking




Intel 82599 VF






Intel 82599 VF







For more information, see the following:

Release Notes

  • C4 and C5 instances require 64-bit HVM AMIs. They have high-memory (up to 144 GiB of RAM), and require a 64-bit operating system to take advantage of that capacity. HVM AMIs provide superior performance in comparison to paravirtual (PV) AMIs on high-memory instance types. In addition, you must use an HVM AMI to take advantage of enhanced networking.

  • With C5 instances, EBS volumes are exposed as NVMe block devices. C5 instances require EBS-backed AMIs with the NVMe and Elastic Network Adapter (ENA) drivers installed. The following AMIs meet these requirements:

    • Amazon Linux 2014.03 or later

    • Ubuntu 14.04 or later

    • SUSE Linux Enterprise Server 12 or later

    • Red Hat Enterprise Linux 7.4 or later

    • CentOS 7 or later

    • FreeBSD 11.1-RELEASE

    • Windows Server 2012 R2

    • Windows Server 2016

  • C5 instances support a maximum of 27 EBS volumes plus ENI attachments. For example, c5.2xlarge instances support 4 network interfaces. Every instance has at least 1 network interface. If you have a c5.2xlarge instance with 3 additional ENI attachments, you can attach 24 EBS volumes to that instance.

  • C5 instances should have acpid installed to support clean shutdown through API requests.

  • 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.