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    Elastic Compute Service:CPU options of instance types in compute-optimized instance families

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    Elastic Compute Service:CPU options of instance types in compute-optimized instance families

    Last Updated:Jun 13, 2025

    When you call the RunInstances operation to create Elastic Compute Service (ECS) instances, you can specify CPU options for specific instance types. The CPU options are determined by the number of physical CPU cores and the number of threads per core. You can adjust the number of vCPUs allocated to an ECS instance by changing the number of physical CPU cores and the number of threads per core based on your application performance requirements. This approach helps you improve performance and control costs. This topic lists the values related to the number of physical CPU cores and the number of threads per core for each instance type in compute-optimized instance families. You can use these values when specifying CPU options.

    Values related to the number of physical CPU cores and the number of threads per core of c8i 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.c8i.large

    2

    1

    2

    1, 2

    ecs.c8i.xlarge

    4

    2

    2

    1, 2

    ecs.c8i.2xlarge

    8

    4

    2

    1, 2

    ecs.c8i.3xlarge

    12

    6

    2

    1, 2

    ecs.c8i.4xlarge

    16

    8

    2

    1, 2

    ecs.c8i.6xlarge

    24

    12

    2

    1, 2

    ecs.c8i.8xlarge

    32

    16

    2

    1, 2

    ecs.c8i.12xlarge

    48

    24

    2

    1, 2

    ecs.c8i.16xlarge

    64

    32

    2

    1, 2

    ecs.c8i.24xlarge

    96

    48

    2

    1, 2

    ecs.c8i.48xlarge

    192

    96

    2

    1, 2

    Values related to the number of physical CPU cores and the number of threads per core of c7a 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.c7a.large

    2

    1

    2

    1, 2

    ecs.c7a.xlarge

    4

    2

    2

    1, 2

    ecs.c7a.2xlarge

    8

    4

    2

    1, 2

    ecs.c7a.4xlarge

    16

    8

    2

    1, 2

    ecs.c7a.8xlarge

    32

    16

    2

    1, 2

    ecs.c7a.16xlarge

    64

    32

    2

    1, 2

    ecs.c7a.32xlarge

    128

    64

    2

    1, 2

    Values related to the number of physical CPU cores and the number of threads per core of c7 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.c7.large

    2

    1

    2

    1, 2

    ecs.c7.xlarge

    4

    2

    2

    1, 2

    ecs.c7.2xlarge

    8

    2, 4

    2

    1, 2

    ecs.c7.3xlarge

    12

    2, 4, 6

    2

    1, 2

    ecs.c7.4xlarge

    16

    2, 4, 6, 8

    2

    1, 2

    ecs.c7.6xlarge

    24

    2, 4, 6, 8, 10, 12

    2

    1, 2

    ecs.c7.8xlarge

    32

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

    2

    1, 2

    ecs.c7.16xlarge

    64

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

    2

    1, 2

    ecs.c7.32xlarge

    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, 64

    2

    1, 2

    Values related to the number of physical CPU cores and the number of threads per core of c6a 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.c6a.large

    2

    1

    2

    1, 2

    ecs.c6a.xlarge

    4

    2

    2

    1, 2

    ecs.c6a.2xlarge

    8

    4

    2

    1, 2

    ecs.c6a.4xlarge

    16

    8

    2

    1, 2

    ecs.c6a.8xlarge

    32

    16

    2

    1, 2

    ecs.c6a.16xlarge

    64

    32

    2

    1, 2

    ecs.c6a.32xlarge

    128

    64

    2

    1, 2

    Values related to the number of physical CPU cores and the number of threads per core of c6 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.c6.large

    2

    1

    2

    1, 2

    ecs.c6.xlarge

    4

    2

    2

    1, 2

    ecs.c6.2xlarge

    8

    2, 4

    2

    1, 2

    ecs.c6.3xlarge

    12

    2, 4, 6

    2

    1, 2

    ecs.c6.4xlarge

    16

    2, 4, 6, 8

    2

    1, 2

    ecs.c6.6xlarge

    24

    2, 4, 6, 8, 10, 12

    2

    1, 2

    ecs.c6.8xlarge

    32

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

    2

    1, 2

    ecs.c6.13xlarge

    52

    2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26

    2

    1, 2

    ecs.c6.26xlarge

    104

    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

    2

    1, 2

    References

    • After you obtain the valid values for the number of physical CPU cores and the number of threads per core of an instance type, you can change the CPU options of the instance type based on your business requirements. For more information, see Change CPU options.

    • Hyper-threading (HT) enables two threads to concurrently run on a single physical CPU core as vCPUs. To create an ECS instance that uses only physical CPU cores, you need to disable HT for the instance. For more information, see Change CPU options.