On-Package PCH, The First Single Chip Haswell

In 2010, with Clarkdale and Arrandale, Intel went from a 3-chip platform solution (CPU, IOH/MCH, ICH) down to a 2-chip platform (CPU + PCH). With Haswell, we see the first instantiation of a single-chip Core platform.

With the 8-series chipset, Intel moved from a 65nm process on the 7-series chipset to 32nm, skipping 45nm entirely. An older, less mobile-focused Intel would try to keep its chipsets on the oldest, economically sensible node possible, but these days things are different. The move to 32nm cuts TDP down considerably. Intel hasn’t publicly documented the power consumption any of its ultra mobile chipsets, but if we look at QM77 to QM87 we see a 34% decrease in TDP.

In Haswell desktop and standard voltage mobile parts, the 8-series chipset remains a an off-chip solution in a discrete package. With Haswell ULT and ULX (U and Y series SKUs), the 8-series PCH (Platform Controller Hub) moves on-package. Since it’s on-package, the TDP of the PCH is included in the overall TDP of the processor.

Bringing the PCH on-package not only saves space on the motherboard, but it also reduces the power needed to communicate with the chip. Signals no longer have to travel off die, through the package, via traces on the motherboard to the PCH. Instead you get much lower power on-package communication.

Intel also changed the interface between the CPU and PCH to a new on-package interface instead of DMI. Presumably Intel’s OPI is designed for much lower power operation.

Although PCIe support remains on the PCH (6 PCIe 2.0 lanes), there’s no external PCIe interface from the CPU itself. Any hopes for pairing a meaningfully high performance discrete GPU with Haswell ULT are dead. We didn’t see a ton of Ivy Bridge Ultrabooks with discrete GPUs, but the option simply won’t exist this time around. All of the sudden the creation of Intel’s 28W Haswell ULT with GT3 graphics makes a lot more sense. Haswell ULT lacks native VGA support. Update: NVIDIA tells me that it fully supports running a dGPU off of a x4 connection to the PCH. It's not the ideal solution, but discrete GPUs will still technically be possible with Haswell ULT.

Intel adds SDIO support. USB 3 and 6Gbps SATA are both there as well (although with fewer max ports supported compared to the desktop PCH, up to 4 and 3 respectively). There’s also a lot more sharing of bandwidth between individual PCIe lanes and USB/SATA. These limits shouldn’t be an issue given the port/drive configuration of most Ultrabooks.

Introduction Haswell ULT: Platform Power Improvements
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  • FwFred - Monday, June 10, 2013 - link

    Single package instead of two, integrated VRs instead of discrete. Perhaps this allows a smaller mainboard and allows a bigger battery?
  • piroroadkill - Monday, June 10, 2013 - link

    Not impressed.
    Yeah, the idle time battery life is better, but that GPU is super-lousy. In my opinion, Intel have done themselves a massive disservice by making crappy GPUs available with Haswell. The choice should be only 5100 and 5200. The others are a total waste of time, and barely interesting over HD 4000.
  • nunomoreira10 - Monday, June 10, 2013 - link

    There is not a single 5100 17w sku, and the reason is power.
    intel is going the nvidea and amd road, choices, this is the budget i7, want more, pay more.
  • mikebelle - Monday, June 10, 2013 - link

    I still think he has a point though. While some consumers may prefer the battery life and/or cost savings. Intel seems to have made it very difficult to get access to any of there 5000 series graphics. I wouldn't be surprised to see Iris and Iris Pro come to a few Core i5 parts during Haswell's "refresh".
  • samkathungu - Monday, June 10, 2013 - link

    Is it just me or are the releases coming from Intel about all the flavours of Haswell getting a little confusing? Probably a better communications strategy next time will benefit consumers.
    The confusion over what graphics ships with the desktop or mobile parts is not pleasant.
  • vipw - Monday, June 10, 2013 - link

    Maybe I'm bad at counting, but it still looks like there are two chips on the package.
  • sheh - Monday, June 10, 2013 - link

    When are the i5 43xxM and 42xxM are going to be available?
  • darthrevan13 - Monday, June 10, 2013 - link

    So no more PCIe 2.0? Will Thunderbolt be available for ULT/ULX processors? You could in theory connect a dGPU through that, right?
  • Sugardaddy - Monday, June 10, 2013 - link

    On page 2, you state that "any hopes for pairing a meaningfully high performance discrete GPU with Haswell ULT are dead."

    But there is a lot of Ultrabooks coming out like the Aspire S3-392 with a discrete GT 735M, which is probably 50%-100% faster than the 620M in last year's Asus UX32VD.

    How does that fit together? Is the 735M not "meaningfully faster" than HD4400/HD5000?
  • extide - Monday, June 10, 2013 - link

    I was hoping charlie would be wrong. Sadly, he was right, Intel took away PCIe 3.0 and all CPU based PCIe lanes from this CPU. This is how the kill off AMD/nVidia competition, make it literally not an option. Scary as hell, I hope they don't start doing this to higher TDP SKU's.

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