Feeds

Idle wild: how Intel's mobile Core i7 speeds up to slow down

Turbo Boost, Thread Parking and the drive for low-power performance

  • alert
  • submit to reddit

Mobile application security vulnerability report

Intel's first mobile Core i7 processors - codenamed 'Clarksfield' - incorporate a feature the chip company is calling Turbo Boost. It's not new - the technology is a part of every 'Nehalem' architecture-based CPU the company has released to date.

So, Turbo Boost can be found in desktop chips and it's in Xeon server parts too. But it really comes into its own in processors produced for laptops.

Intel Clarksfield

Intel's Clarksfield: all four cores can be powered down to zero

The mobile Core i7s are all quad-core parts, and while model numbers and operating clock frequencies differ, Turbo Boost works the same way in each case. The technology takes feedback from on-chip thermal sensor and watches how the operating system is scheduling work on the available cores. Using both sources, Turbo Boost sees if it can lift the chip's clock speed and operating voltage above baseline.

A 2GHz chip with threads scheduled on all four cores has the scope to be dynamically overclocked up to 2.26GHz, provided there's room within the chip's thermal envelope to do so. That's 55W on the 2GHz Core i7-920XM, falling to 45W with the 1.73GHz i7-820QM and the 1.6GHz i7-720QM.

If an application is only making use of two of the four cores, the remaining pair of processing units can be powered right down to zero, dropping the chip's overall thermal output and allowing the two running cores to be clocked anywhere up to 3.06GHz.

Intel Turbo Boost

The current Clarksfield line-up

A one-thread, one-core application presents even more room for lifting the clock frequency as the other three cores are sent to deep sleep, slashing the heat coming off them and, in turn, allowing Turbo Boost to up the one core's clock frequency up to 3.2GHz - 60 per cent higher than the stock clock speed.

Boost IT visibility and business value

More from The Register

next story
iPad? More like iFAD: We reveal why Apple fell into IBM's arms
But never fear fanbois, you're still lapping up iPhones, Macs
For Lenovo US, 8-inch Windows tablets are DEAD – long live 8-inch Windows tablets
Reports it's killing off smaller slabs are greatly exaggerated
Cheer up, Nokia fans. It can start making mobes again in 18 months
The real winner of the Nokia sale is *drumroll* ... Nokia
Microsoft unsheathes cheap Android-killer: Behold, the Lumia 530
Say it with us: I'm King of the Landfill-ill-ill-ill
Seventh-gen SPARC silicon will accelerate Oracle databases
Uncle Larry's mutually-optimised stack to become clearer in August
EU dons gloves, pokes Google's deals with Android mobe makers
El Reg cops a squint at investigatory letters
Apple orders huge MOUNTAIN of 80 MILLION 'Air' iPhone 6s
Bigger, harder trouser bulges foretold for fanbois
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Reducing security risks from open source software
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.