Intel Turbo Boost

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Intel Turbo Boost is a technology implemented by Intel in certain versions of their Nehalem-, Sandy-Bridge-, Ivy-Bridge, and Haswell-based CPUs, including Core i5 and Core i7, that enables the processor to run above its base operating frequency via dynamic control of the CPU's clock rate.[1] It is activated when the operating system requests the highest performance state of the processor. Processor performance states are defined by the Advanced Configuration and Power Interface (ACPI) specification, an open standard supported by all major operating systems; no additional software or drivers are required to support the technology.[1] The design concept behind Turbo Boost is commonly referred to as "dynamic overclocking".[2]

The increased clock rate is limited by the processor's power, current and thermal limits, as well as the number of cores currently in use and the maximum frequency of the active cores.[1] When the workload on the processor calls for faster performance, and the processor is below its limits, the processor's clock will increase the operating frequency in regular increments as required to meet demand. Frequency increases occur in increments of 133 MHz for Nehalem microarchitecture processors and 100 MHz for Sandy/Ivy Bridge microarchitecture processors. When any of the electrical or thermal limits are reached, the operating frequency automatically decreases in decrements of 133 MHz/100 MHz until the processor is again operating within its design limits.[1]

History[edit]

An Intel white paper of November 2008[3] discusses "Turbo Boost" technology as a new feature incorporated into Nehalem-based processors released in the same month.[4]

A similar feature called Intel Dynamic Acceleration (IDA) was available on many Core 2 based Centrino platforms.[5] This feature did not receive the marketing treatment given to Turbo Boost. Intel Dynamic Acceleration dynamically changed the core frequency as a function of the number of active cores. When the operating system instructed one of the active cores to enter C3 sleep state using the Advanced Configuration and Power Interface (ACPI), the other active core(s) dynamically accelerated to a higher frequency.

Intel Turbo Boost Technology Monitor, as a GUI utility, could be used to monitor Turbo Boost; this utility has reached the end-of-life state and is no longer available.[citation needed]

Example[edit]

For Core i7-920XM, normal operating frequency is 2.0 GHz. Turbo is indicated as: 2/2/8/9 in which the first number is the multiple of 133⅓ MHz supported when four cores are active, the second number is the multiple for three cores, the third number is for two cores, and the fourth number is for one active core.

Subject to limits on temperature, current and power consumption, the processor can increase its clock speed (from a base frequency of 2.0 GHz) in steps of 133⅓ MHz to:

# of cores active # of Turbo Steps Max frequency Calculation
4 2 2.26 GHz 2000 + (2 × 133) = 2000 + 267 = 2267
2 8 3.06 GHz 2000 + (8 × 133) = 2000 + 1067 = 3067
1 9 3.20 GHz 2000 + (9 × 133) = 2000 + 1200 = 3200

For Core i7-2920XM, normal operating frequency is 2.5 GHz. Turbo is indicated as: 7/7/9/10 in which the first number is the multiple of 100 MHz supported when four cores are active, the second number is the multiple for three cores, the third number is for two cores, and the fourth number is for one active core.

Subject to limits on temperature, current and power consumption, the processor can increase its clock speed (from a base frequency of 2.5 GHz)in steps of 100 MHz to:

# of cores active # of Turbo Steps Max frequency Calculation
4 7 3.20 GHz 2500 + (7 × 100) = 2500 + 700 = 3200
2 9 3.40 GHz 2500 + (9 × 100) = 2500 + 900 = 3400
1 10 3.50 GHz 2500 + (10 × 100) = 2500 + 1000 = 3500

See also[edit]

References[edit]

  1. ^ a b c d http://www.intel.com/technology/turboboost/
  2. ^ Molka, Daniel; Daniel Hackenberg; Robert Schöne; Matthias S. Müller (September 2009). "Memory Performance and Cache Coherency Effects on an Intel Nehalem Multiprocessor System". 18th International Conference on Parallel Architectures and Compilation Techniques. pp. 261–270. doi:10.1109/PACT.2009.22. ISBN 978-0-7695-3771-9. Retrieved 2010-05-13. "[...] processors based on the Nehalem microarchitecture feature a dynamic overclocking mechanism (Intel Turbo Boost Technology) that allows the processor to raise core frequencies as long as the thermal limit is not exceeded." 
  3. ^ "Intel Turbo Boost Technology in Intel Core Microarchitecture (Nehalem) Based Processors" (PDF). Intel Corporation. November 2008. p. 5. Retrieved 2010-05-13. "Intel Core Microarchitecture (Nehalem) based processors incorporate a new feature: Intel Turbo Boost technology." 
  4. ^ "Intel Launches Fastest Processor on the Planet" (Press release). Intel. 2008-11-17. Retrieved 2010-05-13. "Intel Corporation introduced its most advanced desktop processor ever, the Intel Core i7 processor. The Core i7 processor is the first member of a new family of Nehalem processor designs [....]" 
  5. ^ Tech ARP - Intel Dynamic Acceleration

External links[edit]