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    Elastic Compute Service:CPU options for memory-optimized instance types

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    Elastic Compute Service:CPU options for memory-optimized instance types

    Last Updated:Apr 27, 2026

    Configure physical CPU cores and threads per core for memory-optimized ECS instance types to optimize vCPU allocation for performance and cost.

    r9i instance types

    Instance type

    Default number of vCPUs

    Valid values for the number of physical CPU cores

    Default number of threads per core

    Valid values for the number of threads per core

    ecs.r9i.large

    2

    1

    2

    1 and 2

    ecs.r9i.xlarge

    4

    2

    2

    1 and 2

    ecs.r9i.2xlarge

    8

    2 and 4

    2

    1 and 2

    ecs.r9i.3xlarge

    12

    2, 4, and 6

    2

    1 and 2

    ecs.r9i.4xlarge

    16

    2, 4, 6, and 8

    2

    1 and 2

    ecs.r9i.6xlarge

    24

    2, 4, 6, 8, 10, and 12

    2

    1 and 2

    ecs.r9i.8xlarge

    32

    2, 4, 6, 8, 10, 12, 14, and 16

    2

    1 and 2

    ecs.r9i.12xlarge

    48

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24

    2

    1 and 2

    ecs.r9i.16xlarge

    64

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32

    2

    1 and 2

    ecs.r9i.24xlarge

    96

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, and 48

    2

    1 and 2

    ecs.r9i.32xlarge

    128

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, and 64

    2

    1 and 2

    ecs.r9i.48xlarge

    192

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, and 96

    2

    1 and 2

    r8a instance types

    Instance type

    Default number of vCPUs

    Valid values for the number of physical CPU cores

    Default number of threads per core

    Valid values for the number of threads per core

    ecs.r8a.large

    2

    1

    2

    1 and 2

    ecs.r8a.xlarge

    4

    2

    2

    1 and 2

    ecs.r8a.2xlarge

    8

    2 and 4

    2

    1 and 2

    ecs.r8a.4xlarge

    16

    2, 4, 6, and 8

    2

    1 and 2

    ecs.r8a.8xlarge

    32

    2, 4, 6, 8, 10, 12, 14, and 16

    2

    1 and 2

    ecs.r8a.12xlarge

    48

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24

    2

    1 and 2

    ecs.r8a.16xlarge

    64

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32

    2

    1 and 2

    ecs.r8a.24xlarge

    96

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, and 48

    2

    1 and 2

    ecs.r8a.32xlarge

    128

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, and 64

    2

    1 and 2

    ecs.r8a.48xlarge

    192

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, and 96

    2

    1 and 2

    r8ae instance types

    Instance type

    Default number of vCPUs

    Valid values for the number of physical CPU cores

    Default number of threads per core

    Valid values for the number of threads per core

    ecs.r8ae.large

    2

    1

    2

    1 and 2

    ecs.r8ae.xlarge

    4

    2

    2

    1 and 2

    ecs.r8ae.2xlarge

    8

    2 and 4

    2

    1 and 2

    ecs.r8ae.4xlarge

    16

    2, 4, 6, and 8

    2

    1 and 2

    ecs.r8ae.8xlarge

    32

    2, 4, 6, 8, 10, 12, 14, and 16

    2

    1 and 2

    r8i instance types

    Instance type

    Default number of vCPUs

    Valid values for the number of physical CPU cores

    Default number of threads per core

    Valid values for the number of threads per core

    ecs.r8i.large

    2

    1

    2

    1 and 2

    ecs.r8i.xlarge

    4

    2

    2

    1 and 2

    ecs.r8i.2xlarge

    8

    2 and 4

    2

    1 and 2

    ecs.r8i.3xlarge

    12

    2, 4, and 6

    2

    1 and 2

    ecs.r8i.4xlarge

    16

    2, 4, 6, and 8

    2

    1 and 2

    ecs.r8i.6xlarge

    24

    2, 4, 6, 8, 10, and 12

    2

    1 and 2

    ecs.r8i.8xlarge

    32

    2, 4, 6, 8, 10, 12, 14, and 16

    2

    1 and 2

    ecs.r8i.12xlarge

    48

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24

    2

    1 and 2

    ecs.r8i.16xlarge

    64

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32

    2

    1 and 2

    ecs.r8i.32xlarge

    128

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, and 64

    2

    1 and 2

    r7a instance types

    Instance type

    Default number of vCPUs

    Valid values for the number of physical CPU cores

    Default number of threads per core

    Valid values for the number of threads per core

    ecs.r7a.large

    2

    1

    2

    1 and 2

    ecs.r7a.xlarge

    4

    2

    2

    1 and 2

    ecs.r7a.2xlarge

    8

    2 and 4

    2

    1 and 2

    ecs.r7a.4xlarge

    16

    2, 4, 6, and 8

    2

    1 and 2

    ecs.r7a.8xlarge

    32

    2, 4, 6, 8, 10, 12, 14, and 16

    2

    1, 2

    ecs.r7a.16xlarge

    64

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32

    2

    1 and 2

    ecs.r7a.32xlarge

    128

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, and 64

    2

    1 and 2

    r7 instance types

    Instance type

    Default number of vCPUs

    Valid values for the number of physical CPU cores

    Default number of threads per core

    Valid values for the number of threads per core

    ecs.r7.large

    2

    1

    2

    1 and 2

    ecs.r7.xlarge

    4

    2

    2

    1 and 2

    ecs.r7.2xlarge

    8

    2 and 4

    2

    1 and 2

    ecs.r7.3xlarge

    12

    2, 4, and 6

    2

    1 and 2

    ecs.r7.4xlarge

    16

    2, 4, 6, and 8

    2

    1 and 2

    ecs.r7.6xlarge

    24

    2, 4, 6, 8, 10, and 12

    2

    1 and 2

    ecs.r7.8xlarge

    32

    2, 4, 6, 8, 10, 12, 14, and 16

    2

    1 and 2

    ecs.r7.16xlarge

    64

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32

    2

    1 and 2

    ecs.r7.32xlarge

    128

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, and 64

    2

    1 and 2

    r6a instance types

    Instance type

    Default number of vCPUs

    Valid values for the number of physical CPU cores

    Default number of threads per core

    Valid values for the number of threads per core

    ecs.r6a.large

    2

    1

    2

    1 and 2

    ecs.r6a.xlarge

    4

    2

    2

    1 and 2

    ecs.r6a.2xlarge

    8

    2 and 4

    2

    1 and 2

    ecs.r6a.4xlarge

    16

    2, 4, 6, and 8

    2

    1 and 2

    ecs.r6a.8xlarge

    32

    2, 4, 6, 8, 10, 12, 14, and 16

    2

    1 and 2

    ecs.r6a.16xlarge

    64

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32

    2

    1 and 2

    References

    • Change CPU options for an instance type based on the valid physical CPU core counts and threads-per-core values listed in this topic.

    • Hyper-threading (HT) runs two threads on a single physical CPU core as vCPUs. To use only physical cores, disable HT when specifying CPU options.