Platform Retargeting

Since the introduction of Conroe/Merom back in 2006 Intel has been prioritizing notebooks for the majority of its processor designs. The TDP target for these architectures was set around 35 - 45W. Higher and lower TDPs were hit by binning and scaling voltage. The rule of thumb is a single architecture can efficiently cover an order of magnitude of TDPs. In the case of these architectures we saw them scale all the way up to 130W and all the way down to 17W.

In the middle of 2011 Intel announced its Ultrabook initiative, and at the same time mentioned that Haswell would shift Intel's notebook design target from 35 - 45W down to 10 - 20W.

At the time I didn't think too much about the new design target, but everything makes a lot more sense now. This isn't a "simple" architectural shift, it's a complete rethinking of how Intel approaches platform design. More importantly than Haswell's 10 - 20W design point, is the new expanded SoC design target. I'll get to the second part shortly.

Platform Power

There will be four client focused categories of Haswell, and I can only talk about three of them now. There are the standard voltage desktop parts, the mobile parts and the ultra-mobile parts: Haswell, Haswell M and Haswell U. There's a fourth category of Haswell that may happen but a lot is still up in the air on that line.

Of the three that Intel is talking about now, the first two (Haswell/Haswell M) don't do anything revolutionary on the platform power side. Intel is promising around a 20% reduction in platform power compared to Sandy Bridge, but not the order of magnitude improvement it promised at IDF. These platforms are still two-chip solutions with the SoC and a secondary IO chip similar to what we have today with Ivy Bridge + PCH.

It's the Haswell U/ULT parts that brings about the dramatic change. These will be a single chip solution, with part of the voltage regulation typically found on motherboards moved onto the chip's package instead. There will still be some VR components on the motherboard as far as I can tell, it's the specifics that are lacking at this point (which seems to be much of the theme of this year's IDF).

Seven years ago Intel first demonstrated working silicon with an on-chip North Bridge (now commonplace) and on-package CMOS voltage regulation:

The benefits were two-fold: 1) Intel could manage fine grained voltage regulation with very fast transition times and 2) a tangible reduction in board component count.


2005 - A prototype motherboard using the technology. Note the lack of voltage regulators on the motherboard and the missing GMCH (North Bridge) chip.

The second benefit is very easy to understand from a mobile perspective. Fewer components on a motherboard means smaller form factors and/or more room for other things (e.g. larger battery volume via a reduction in PCB size).

The first benefit made a lot of sense at the time when Intel introduced it, but it makes even more sense when you consider the most dramatic change to Haswell: support for S0ix active idle.

Introduction: Stating the Problem The New Sleep States: S0ix
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  • tipoo - Friday, October 05, 2012 - link

    Speaking of the EUs, is the GT3 part twice as fast as the HD4000 with or without the eDRAM cache? The article seems to imply with, but then what is the performance without it if they've doubled the EUs? Doesn't it seem more likely they doubled performance without the cache, and the cache doubles it beyond that? Reply
  • telephone - Friday, October 05, 2012 - link

    Anand, thanks for the insights. We all enjoyed it very much and look forward to getting the real thing into your labs.

    To clarify some questions:
    As for the design team philosophy, the Hillsboro design team continually tries to outdo the Haifa design team and vice versa. Both teams have access to the other teams' design collateral, as we co-own the tick-tock model.

    Next, the reasons for the "3" clock domains are too complicated (and confidential) to go into. Since designing for "2" clock domains is much simpler, the reason is not that we enjoy pain and misery. Suffice to say, that you are missing a very big piece of the puzzle and accurate conclusions as to why this was done cannot be drawn from the information you have. And the number of clock domains is in quotes because those are not accurate anyhow.

    Sincerely,
    Someone from the Hillsboro Design Team
    Reply
  • Stahn Aileron - Friday, October 05, 2012 - link

    I'm curious as to whether Intel has enough interest to drive the Atom design low enough to hit ARM power level (like Medfield) and integrate an Atom core into a Core CPU design. nVidia introduced a heterogeneous CPU in their Tegra 3 SoC. (Two different ARM core types in the CPU block). From all the stuff I've seen about Intel over the past half decade, I'm pretty sure they have the resources to pull that off. They have top-notch designers and engineers with the basic tech and designs need to start R&D on that, I think.

    On the other hand, if they really are trying to force a Core design in Atom territory... Well, hell ya ^_~ Still, I can't really see Core hitting the sub-1W power levels they've been able to do with Atom (Medfield). I figure using an Atom core for basic S0ix functions would be a little more power efficient than using a Core design, but I'm no silicon engineer. Intel would know about that far better than me.
    Reply
  • jigglywiggly - Friday, October 05, 2012 - link

    wish the onboard gpu was better =/
    woula been nice for a laptop
    Reply
  • tipoo - Friday, October 05, 2012 - link

    2x the HD4000 is pretty decent for integrated. I wonder if that's 2x with or without the eDRAM cache though. Reply
  • ElvenLemming - Friday, October 05, 2012 - link

    It's been known for a while that Haswell was only going to have a moderate improvement in the iGPU and the next big overhaul would be coming with Broadwell. Reply
  • csroc - Friday, October 05, 2012 - link

    This is impressive, it might convince me it's time for a new laptop. On the other hand I also need to build a new desktop workstation and Haswell so far hasn't impressed me in that space. Reply
  • mayankleoboy1 - Friday, October 05, 2012 - link

    Is Intel sacrificing Desktop CPU performance to make an architecture that is geared to the mobile space ? Reply
  • csroc - Friday, October 05, 2012 - link

    It feels that way to me. Mobile performance seems to be their big concern now, that and improving the GPU. Two things I generally can't be bothered to care about when I'm looking to build a new workstation. I suspect I'll build an Ivy Bridge system because I could use it now and see nothing worth getting excited about. Reply
  • dishayu - Friday, October 05, 2012 - link

    I fully share your sentiment. TO be very crude, i don't mind at all, paying for power imporvements, because it will pay back for itself in the long term (by consuming less power AND needing lesser cooling). But i DO mind very much, paying for 40 EUs of GPU on my desktop build which i will not use even for a second. Me, you and many others do not care about on-die graphics and Intel should realize that.

    I don't know why intel can't offer us both GPU and GPU-less options, the way they did with motherboards back in the days? P965 had no graphics, G965 did. Pretty sure it's technologically not an issue.
    Reply

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