Intel's Clarksfield XE--putting the 'hot' in notebooks

At the Intel Developer Forum, OEMs learned how to design laptops around the new Core i7-920XM Extreme Edition that could consume as much as 250 watts of power.

Ready for a 250-watt notebook? Intel is helping its OEMs to design such extremes.

A presentation at the Intel Developer Forum last week discussed how to build notebooks around the Core i7-920XM Extreme Edition mobile processor, code-named Clarksfield XE.

It turns out that when I estimated the maximum power consumption of a 920XM-based laptop at 80 watts to 100 watts, I was way off! (A typical notebook, by the way, averages somewhere between 40 and 90 watts.)

My estimate was reasonable for the kind of typical 920XM laptop I had in mind, but Intel showed how to go so far beyond "typical" that the resulting machine could need a 250-watt power brick.

I looked around, and the biggest power adapter I could find belongs to the Dell Alienware M17x, which needs a 210-watt brick. (I trust someone will tell me if there's a bigger one out there somewhere...Just leave a comment below.)

Intel extreme laptop platform definition
Intel

Consider the list of features shown here, from Intel's presentation: the Extreme Edition processor, naturally; two discrete GPUs; and a 9-cell to 12-cell battery, which could account for two pounds out of the 12-pound target. Elsewhere in the presentation, Intel recommends considering a two-disk RAID storage configuration and discusses overclocking options.

Overclocking has been an optional feature of Extreme Edition processors for a while now. It turns out to be a little easier with the 920XM, which integrates both the CPU cores and the memory controller. This puts the chip firmly in control of the whole process. But most of that control is delegated to the OEM, which can then pass it along to the user.

Although overclocking and brick-like power bricks may be old hat to some, the novel feature in the 920XM is that it allows the user to override the Turbo Mode settings I described in my previous message. The normal limits on TDP (Thermal Design Power), supply current, even CPU temperature can be changed to allow the chip to operate well outside its guaranteed range. This, naturally, voids the warranty, but for many users, that isn't a problem.

Intel provides a software tool, the Intel Extreme Tuning Utility, to help enthusiast users get as close to the limits of the hardware as possible, ideally without going over.

It even works with custom-designed power supplies to exceed the usual limits for processor and memory power. This can cause the chip's power dissipation to soar. Forget the 55-watt TDP specification, at which the chip is guaranteed to be able to run all four cores at 2GHz. With overvolting and all the safety limits disabled, the 920XM can consume over 90 watts running at 3.33GHz with a case temperature of 176 degrees.

With an exceptionally robust thermal solution that can keep the case temperature down to 122 degrees, Intel estimates the chip could run as fast as 3.47GHz. Intel doesn't estimate corresponding dual-core or single-core frequencies. But given that the 920XM can get a 60 percent boost in single-core mode, a speed of 5GHz is at least theoretically within reach.

As exciting as that may be, I am not making any personal promises here. I can only echo Intel's own warning: Improper settings can permanently damage your PC.

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About the author

    Peter N. Glaskowsky is a computer architect in Silicon Valley and a technology analyst for the Envisioneering Group. He has designed chip- and board-level products in the defense and computer industries, managed design teams, and served as editor in chief of the industry newsletter "Microprocessor Report." He is a member of the CNET Blog Network and is not an employee of CNET. Disclosure.

     

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