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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  • broccauley - Tuesday, June 11, 2013 - link

    Were Acer not known for their "Timeline" series of laptops which were known for groundbreaking battery life?
  • smilingcrow - Tuesday, June 18, 2013 - link

    Apple are claiming dramatically improved battery life.
  • deeps6x - Sunday, July 14, 2013 - link

    I just don't get why Intel caved to MS pressure and made touchscreen a requirement for Haswell. Everyone I know who does image editing insists on doing it on a matte screen.

    Metro was a huge mistake.

    Gaah, just too pissed about this to make a coherent comment.

    I want haswell with a matte screen and 13 and 15 inch 'ultrabook' size options. I guess manufacturers will just have to invent some new name to call their matte screen ultrabooks. Perhaps just call them 'laptops' and say screw you and your goof ass naming rules Intel.
  • Xenon14 - Sunday, June 9, 2013 - link

    It would be useful to see productivity and multithreaded benchmarks like Excel and Fritz. It'd be nice if you provide a few charts with higher TDP Cpu's so we can see the relative performance differences.
  • Synaesthesia - Sunday, June 9, 2013 - link

    Wow Anand you delivered! Once again such an in-depth analysis of EVERYTHING relevant to the platform. Nowhere else can I find this information!
  • uditrana - Sunday, June 9, 2013 - link

    Except for one thing. How did they change the backlighting in the S7. I am really interested in knowing.
  • n13L5 - Sunday, June 9, 2013 - link

    yeah, they did a good job doing that on location and before anyone else :D
  • meacupla - Sunday, June 9, 2013 - link

    That's great news.

    Now, I can't wait to see it in surface pro.
  • B3an - Sunday, June 9, 2013 - link

    Yeah Surface Pro with one of these, in a thinner and lighter design (should be possible now) with Windows 8.1 = ultimate device.
  • MrSpadge - Monday, June 10, 2013 - link

    Or the Thinkpad Helix!

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