At Computex Intel announced that Ivy Bridge would be its first processor to support a configurable TDP. Today all CPUs are rated at a single maximum TDP. Mainstream notebook processors fall in the 35 - 45W range, while mainstream desktops are around 65W. As the world embraces mobility and interfaces like Thunderbolt enable new usage models for notebook users (e.g. docking station with a beefy external GPU), Intel had to rethink its power strategy.

Today with a 35W CPU, Intel guarantees the OEM that if it implements a chassis and cooling system capable of dissipating that much heat the chip will operate as intended. If the OEM offers an optional dock or high-performance cooling mode that could cool a higher wattage chip, the CPU can't take advantage of it. Ivy Bridge changes this. 

Ultra low volt (ULV) and extreme edition IVB parts will carry three TDP ratings: nominal, a lower configurable TDP (cTDP down) and an upper configurable TDP (cTDP up). Let's talk about cTDP up first.

ULV Ivy Bridge parts will be rated at 17W, similar to the ULV SNB CPUs that are used in Ultrabooks and the new MacBook Air. Intel will also guarantee these chips at a higher frequency with a TDP of 33W. If the Ivy Bridge MacBook Air could dissipate 17W of heat normally but when placed on a docking station with additional cooling capabilities could remove 33W of heat, the CPU would simply run at a much higher frequency when docked. This goes beyond simple turbo as it exceeds the CPU's nominal TDP, whereas turbo mode is mostly bound by TDP.

The same applies in reverse. If you want the chip to behave as if it were a 13W part instead of a 17W part, that will be possible as well. It's configurable performance based on the current conditions. If you have tons of cooling ability, you get more performance. If you need battery life, you get a chip that makes your system behave like an ultraportable.

The extreme edition IVB parts will also support configurable TDP. 55W parts will be able to go up to 65W or go down to 45W. 

You can expect that Intel will use configurable TDP as a reason for customers to buy the more expensive versions of Ivy Bridge. Ivy Bridge is expected to arrive on notebooks and desktops in April - May 2012.

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  • dagamer34 - Monday, September 12, 2011 - link

    At least on the high end of things, a processor that SpeedSteps can never go over it's configured TDP. The other thing is that I'm not sure the CPU is aware at what power state a laptop is in (either plugged in or battery powered).
  • SlyNine1 - Monday, September 12, 2011 - link

    Dell seemed to manage it, look at the 1545 XPS studio's. They underclocked if it was using to much power for the 90watt PSU, and boy did it underclock and use clock modulation.

    I hope this isn't a way from OEMs to sell higher rated chips then the cooling system can handle.

    Yea I just bought a 3.0ghz chip, why is it only running at 1.9ghz.
  • silverblue - Monday, September 12, 2011 - link

    ...don't the server parts of Bulldozer have a configurable TDP as well? AMD would beat them to market by a good 6 months. The question is, whose implementation is superior? Intel's sounds more seamless whereas AMD's is far more granular but requires software support.
  • KPOM - Monday, September 12, 2011 - link

    Did Intel let OEMs know this when they designed the Ultrabook spec? My concern here is that Ultrabook manufacturers are designing chassis right now to get products to market based on the existing TDP, and that while the chips might be ready in April or May, actual products taking advantage of the scalable TDP might take longer.
  • retrospooty - Monday, September 12, 2011 - link

    All major OEM's are well informed of what is coming and have designs based on it. This is true for all releases.
  • Le_Tobe - Monday, September 12, 2011 - link

    i can see an elevated docking station with external fans cooling down a laptop enough to disipate maybe 10w of additional heat, but i wouldn't trust it enough. especially if this is to make your laptop a desktop replacement. for all i know, i could be ignorant to the amount of heat that is contained in a laptop by placing it on your lap or some other insulating surface.
  • Le_Tobe - Monday, September 12, 2011 - link

    just to clarify, i simply don't trust a whole lot of OEMs to make a product that can safely and fully take advantage of the variable TDP
  • Iketh - Monday, September 12, 2011 - link

    yes... oem "engineers" make me facepalm all too often... how do those morons get in the positions they are in?
  • gramboh - Monday, September 12, 2011 - link

    Do we know what the TDP of the desktop IVB parts will be? This articles seems to allude to 65w? I thought they would be 95w at the top end (2600k) like Sandy Bridge?
  • xxtypersxx - Monday, September 12, 2011 - link

    I agree with the poster commenting on how this differs very little from speedstep. Basically they are taking a 33w chip and making the default speedstep profile 17w, essentially locking the chip into a underclocked/undervolted mode for normal use. However while it may not be anything ground breaking technically, I do think it is pretty exciting from a design possibility standpoint and I will certainly happily accept the added performance potential.

    What I'm not sure of is exactly how the OEM's are going to implement additional docked cooling beyond simply having the fans sping faster. You can put fans in the docking station but simply having them blowing into the stock inlet vents is only going to be a marginal improvement. Alternatively you could have excess metal or fins on the bottom of the laptop that are connected to the main heatsink with heatpips but this would likely become uncomfortably warm during mobile use as well. I am a bit worried that what we will see come out of this is laptops designed with internal cooling that can handle 33w but simply run very quietly when mobile and consuming 17w. While this is nice in its own regard, it would be a tremendous waste of the potential here.

    Where I think this becomes even more exciting is on Windows 8 tablets that dock like the Asus EEE Pad. If the chip can run at a low TDP without fans while in tablet mode but somehow make thermal contact with cooling devices in the laptop base when docked and clock up to a 13w or 17w tdp it would be fantastic.

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