With a multi-core processor, Intel decided to intelligently utilize the power envelopes of the total CPU package in a way that allows for frequency acceleration depending on the current state of the software workload.  If only two of the four cores on a Core i7 processor of today are being utilized, then the processor logic knows that it has "thermal envelope" to work with and will increase the clock speed of the two active cores to improve performance for as long as that state remains the same.  If only one core is active, the frequency could then increase another step or two (133 - 266 MHz).  When all four cores are loaded, the processor would run at its specified clock speed where the thermals were rated and tested at.

In practice, Turbo technology from Intel ended up being much less dynamic that we thought it would be over the life of Bloomfield, Lynnfield and then Clarkdale.  The states were very repeatable and very predictable - something that Intel still indicates is one of the goals of the technology. 

In practice, this feature allows Intel to target both multiple cores and higher frequencies with Nehalem-based parts.  Before this, many PC users were forced to decide between getting a dual-core CPU with a higher frequency or a quad-core CPU with a lower frequency, thus deciding their processing fate.  Turbo Boost technology allows users to get the best of both worlds - higher frequencies with fewer cores when your workload demands it and more cores at slightly lower clock speeds when that makes sense. 

The Next-Generation Turbo Boost Technology

At IDF this week, Intel is revealing much more information about the new Sandy Bridge processor architecture and one of many interesting features is a new version of Turbo Boost and how it functions with the platform.  For several hours all the detail Intel would give us is that the new Turbo mode "gave users a boost in responsiveness when they need it most."  There were also several references to the CPU having this ability for 15-20 seconds; needless to say I was incredibly curious what all of this actually translated into from a technical angle. 

After spending some time with a handful of Sandy Bridge engineers and specifically asking about the next-generation Turbo Boost technology, I think we have a good grasp of what it is, how it works and how it affects many different aspects of the new Intel platform.  It turns that Intel has enhanced the way the theories of Turbo Boost are applied to the real-world scenarios.  I have created a handful of diagrams to try to visualize the difference.