CPU platforms

When you create a virtual machine (VM) or bare metal instance using Compute Engine, you specify a machine series and a machine type for the instance. The machine type determines what CPU platform the compute instance runs on.

A CPU platform offers multiple physical processors, and each of these processors is referred to as a core. For the processors available on Compute Engine, a single CPU core can run as multiple hardware threads through Simultaneous multithreading (SMT), which is known on Intel processors as Intel Hyper-Threading Technology. On Compute Engine, each hardware thread is called a virtual CPU (vCPU). Some machine series don't use SMT, and each vCPU instead represents a core. When vCPUs are reported to the instance as occupying different virtual cores, Compute Engine verifies that these vCPUs never share the same physical core.

The machine type of your compute instance specifies its number of vCPUs, and you can infer its number of physical CPU cores using the default vCPU per core ratio for that machine series:

  • For the C4A, N4A, T2D, T2A, H4D, H3, and A4X machine series, Compute Engine instances always have one vCPU per core.
  • For all other machine series, the compute instances have two vCPUs per core by default.

You can optionally set the number of threads per core , to a non-default value, which might benefit some workloads. Importantly, when you do this, the machine type of your compute instance no longer reflects the correct number of vCPUs. Instead, the pricing and number of physical CPU cores remains the same as it would be for the default two vCPUs per core ratio, and the number of vCPUs is half of the value indicated by the machine type.

Frequency behavior

The processor tables in the following sections describe the hardware specifications of the CPUs that are available with Compute Engine, but keep the following points in mind:

  • Frequency: A PC's frequency, or clock speed, measures the number of cycles the CPU executes per second, measured in GHz (gigahertz). Generally, higher frequencies indicate better performance. However, different CPU designs handle instructions differently, so an older CPU with a higher clock speed can be outperformed by a newer CPU with a lower clock speed because the newer architecture deals with instructions more efficiently.

  • Base frequency: The frequency at which the CPU runs when the system is idle or under light load. When running at its base frequency, the CPU draws less power and produces less heat.

    A compute instance's guest environment reflects the base frequency, regardless of what frequency the CPU is actually running at.

  • All-core turbo frequency: The frequency at which each CPU typically runs when all cores in the socket are not idle at the same time. Different workloads place different demands on a system's CPU. Boost technologies address this difference and help processes adapt to the workload demands by increasing the CPU's frequency.

    • Most compute instances get the all-core turbo frequency, even if only the base frequency is advertised to the guest environment.
    • Ampere Altra Arm processors can provide more predictable performance because the frequency for Arm processors is always the all-core turbo frequency.

    • C4 instances and C4N instances are able to run at all-core-max turbo frequency by setting the AdvancedMachineFeature field to ALL_CORE_MAX. If this field is unset, the instance runs at the default setting, which is unrestricted frequency.

      The ALL_CORE_MAX setting isn't available with C4D or C4A compute instances.

  • Max turbo frequency: The frequency a CPU targets when stressed by a demanding application like a video game or design modeling application. It's the maximum single-core frequency that a CPU achieves without overclocking.

  • Processor power management technologies: Intel processors support multiple technologies to optimize the power consumption. These technologies are divided into two categories, or states:

    • C-states are states when the CPU has reduced or turned off selected functions.
    • P-states provide a way to scale the frequency and voltage at which the processor runs so as to reduce the power consumption of the CPU.

    All C4 and C4N machine types, and certain C2 (30, 60 vCPUs), C2D (56, 112 vCPUs) and M2 (208, 416 vCPUs) machine types support instance-provided C-state hints by way of the MWAIT instruction.

    Compute Engine instances don't provide any facilities for customer control of P-states.

x86 processors

For most x86 processors, each vCPU is implemented as a single hardware thread.

Intel processors

On Intel Xeon processors, Intel Hyper-Threading Technology supports multiple threads running concurrently on each core. The machine type of your compute instance determines the number of its vCPUs and memory.

The H3 machine series doesn't use hyper-threading, and one vCPU represents one physical core.

CPU processor Processor SKU Supported machine series and types Base frequency (GHz) All-core turbo frequency (GHz) Single-core max turbo frequency (GHz)
Intel Xeon Scalable Processor
(Granite Rapids)
6th generation
Intel Xeon Platinum 6985P-C Processor
 2.81 3.9 4.2
Intel Xeon Scalable Processor
(Emerald Rapids)
5th generation
 Intel Xeon Platinum 8581C Processor
 2.1 2.9 4.0
2.3 3.1 4.0
2.1 2.9 4.0
2.1 2.9 3.3
Intel Xeon Scalable Processor
(Sapphire Rapids)
4th generation		 Intel Xeon Platinum 8490H Processor 1.9 2.9 3.5
Intel Xeon Platinum 8481C Processor 2.2 3.0 3.0
2.2 3.0 3.8
2.0 3.8 2.9
Intel Xeon Scalable Processor (Ice Lake)
3rd Generation		 Intel Xeon Platinum
8373C Processor		 2.6 3.4 3.5
Intel Xeon Scalable Processor (Cascade Lake)
2nd Generation
Intel Xeon Gold 6268CL Processor 2.8 3.4 3.9
Intel Xeon Gold 6253CL Processor 3.1 3.8 3.9
Intel Xeon Platinum 8280L Processor 2.5 3.4 4.0
Intel Xeon Platinum 8273CL Processor 2.2 2.9 3.7
Intel Xeon Scalable Processor (Skylake)
1st Generation		 Intel Xeon Scalable Platinum 8173M Processor 2.0 2.7 3.5
Intel Xeon E7 (Broadwell E7) Intel Xeon E7-8880V4 Processor 2.2 2.6 3.3
Intel Xeon E5 v4 (Broadwell E5) Intel Xeon E5-2696V4 Processor 2.2 2.8 3.7
Intel Xeon E5 v3 (Haswell) Intel Xeon E5-2696V3 Processor 2.3 2.8 3.8
Intel Xeon E5 v2 (Ivy Bridge) Intel Xeon E5-2696V2 Processor 2.5 3.1 3.5
Intel Xeon E5 (Sandy Bridge) Intel Xeon E5-2689 Processor 2.6 3.2 3.6

1C4 machine types that use the Intel Granite Rapids CPU have a base frequency of 2.8, however vPMU will present 2.3 for compatibility purposes.

2N2 machine types that have 96 or more vCPUs require the Intel Ice Lake CPU.

AMD processors

AMD processors provide optimized performance and scalability using SMT. In almost all cases, Compute Engine uses two threads per core, and each vCPU is one thread. H4D and Tau T2D are the exceptions where Compute Engine uses one thread per core and each vCPU maps to a physical core.

The machine type of your compute instance determines the number of vCPUs and amount of memory allocated to the instance.

CPU processor Processor SKU Supported machine series Base frequency (GHz) Effective frequency (GHz) Max boost frequency (GHz)
AMD EPYC Turin
5th Generation		 AMD EPYC 9B45 2.7 3.5 4.1
AMD EPYC Genoa
4th Generation		 AMD EPYC 9B14