Can You Switch an Amazon EC2 Instance from Intel to AMD?

Yes, Amazon EC2 allows customers to switch an existing stopped Amazon EBS-backed instance from an Intel processor instance type to an AMD processor instance type because both processor families share the same x86_64 instruction set architecture. This transition is a straightforward configuration update that enables organizations to optimize compute costs while maintaining the existing operating system, attached Elastic Block Store volumes, and network interface configurations. Before initiating the change, administrators must verify that the current instance meets specific virtualization, driver, and storage prerequisites to ensure a seamless boot process on the new underlying hardware.

Understanding x86_64 Architecture Compatibility

Both Intel Xeon and AMD EPYC processors deployed in Amazon EC2 utilize the 64-bit x86 (x86_64) architecture. Because the underlying instruction set is identical across both processor manufacturers, an Amazon Machine Image (AMI) compiled for x86_64 runs natively on both Intel-based instances (such as m5.large or c6i.xlarge) and AMD-based instances (such as m5a.large or c6a.xlarge).

Unlike migrating to an AWS Graviton instance—which requires an arm64 architecture and an entirely new operating system image—switching between Intel and AMD instances only requires modifying the instance type attribute while the instance is in a stopped state.

Prerequisites for Switching from Intel to AMD

Before modifying the instance type, you must confirm that your existing EC2 instance satisfies several technical requirements:

• EBS-Backed Root Volume: Only Amazon EBS-backed instances can be stopped and resized. Instance store-backed instances do not support stopping; migrating them requires launching a brand-new instance from an AMI.
• AWS Nitro System Compatibility: All AMD-based EC2 instance families (such as t3a, m5a, m6a, m7a, c5a, c6a, c7a, r5a, r6a, and r7a) are built on the AWS Nitro System. If you are migrating from an older-generation Intel instance (such as m4, c4, or t2), your operating system must have the Elastic Network Adapter (ENA) and NVMe drivers installed and enabled before switching.
• Virtualization Type: The target AMD instance requires Hardware Virtual Machine (HVM) virtualization. Legacy Paravirtual (PV) instances cannot be converted to AMD instance types.
• Placement Group Constraints: If the stopped instance belongs to a cluster placement group, verify that the target AMD instance type is supported within that placement group configuration.

Instance Family Mapping and Cost Calculation

AWS uses the a suffix in the instance family name to designate AMD EPYC processors, while standard numbering or the i suffix designates Intel Xeon processors.

AMD instances generally provide up to a 10% price reduction compared to comparable Intel instances in the same generation. When evaluating the monthly cost difference between an Intel rate \(R_{\text{Intel}}\) and an AMD rate \(R_{\text{AMD}}\) over \(H\) running hours, the total savings \(S\) is calculated as:

\[S = (R_{\text{Intel}} - R_{\text{AMD}}) \times H\]

And the percentage reduction \(P\) is expressed as:

\[P = \left( \frac{R_{\text{Intel}} - R_{\text{AMD}}}{R_{\text{Intel}}} \right) \times 100\]

How to Change the Instance Type Using the AWS Management Console

1. Open the Amazon EC2 console and navigate to the Instances section.
2. Select the running Intel-based instance you want to convert.
3. Choose Instance state, then select Stop instance. Wait for the instance state to transition completely to Stopped.
4. With the instance still selected, choose Actions, navigate to Instance settings, and select Change instance type.
5. In the Change instance type dialog box, select the desired AMD instance type (for example, switching from m6i.large to m6a.large) and click Apply.
6. Choose Instance state and select Start instance to boot the instance on the AMD hardware.

How to Change the Instance Type Using the AWS CLI

You can also perform the switch programmatically using the AWS Command Line Interface (CLI). Replace i-0123456789abcdef0 with your specific instance ID.

First, stop the running EC2 instance and wait for it to reach the stopped state:

aws ec2 stop-instances --instance-ids i-0123456789abcdef0
aws ec2 wait instance-stopped --instance-ids i-0123456789abcdef0

Next, modify the instanceType attribute to the target AMD instance type:

aws ec2 modify-instance-attribute \
    --instance-id i-0123456789abcdef0 \
    --instance-type "{\"Value\": \"m6a.large\"}"

Finally, start the instance back up:

aws ec2 start-instances --instance-ids i-0123456789abcdef0

Post-Switch Considerations

When you stop and start an EC2 instance to change its instance type, keep the following operational behaviors in mind:

• Public IPv4 Addresses: Stopping an instance releases its auto-assigned public IPv4 address. If your workload relies on a static public IP address, associate an Elastic IP address with the instance before stopping it.
• Instance Store Volumes: If your original Intel instance included ephemeral instance store volumes (such as an m5d.large), any data on those ephemeral volumes is permanently erased when the instance stops.
• CPU-Specific Software Optimizations: While standard x86_64 binaries run seamlessly on both Intel and AMD processors, applications compiled strictly with Intel-specific instruction extensions (such as Intel AVX-512 on generations where the target AMD processor does not support it, or older versions of the Intel Math Kernel Library) should be tested to ensure expected performance and compatibility.