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Haswell-E Core i7-5820K Will Only Have 28 PCI-Express Lanes

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Leaked Gigabyte X99 motherboard manuals appear to confirm that the Core i7-5820K will only be able to address 28 PCI-Express lanes, in contrast to the 40 lanes of its superior counterparts.

As it turns out, and as we already suspected, not all of the Haswell-E CPUs will have the same number of PCI-Express lanes. Both the Core i7-5960X and the Core i7-5930K will be able to address 40 PCI-Express lanes, but the cheapest Core i7-5820K will only have access to 28 lanes. TechPowerUp forum member "623" has seemingly confirmed this through leaked manuals of Gigabyte's X99 motherboards.

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CPUCores/ThreadsFrequencyL3 CachePCI-Express LanesTDPExpected Price
i7-5820K6 / 123.3 GHz12 MB28140 W$400
i7-5930K6 / 123.5 GHz15 MB40140 W$600
i7-5960X8 / 163.0 GHz20 MB40140 W$1000+

Of course, this shouldn't come as too much of a surprise. Being able to grab a 6-core Haswell-E processor for the rumored price of $400 makes for a good deal, and there must be a concession made somewhere. While the Core i7-5960X and the Core i7-5930K will be able to address triple-GPU configurations with 16-16-8 lanes, the Core i7-5820K will only manage a 16-8-4 configuration, at best. This leaves the third GPU quite choked, and if you have any additional PCI-Express devices operating over lanes that are wired directly to the CPU, you will run into even more issues. We would have hoped that the i7-5820K would be able to address the slots in an 8-8-8 configuration; however, the manuals posted make no mention of such a configuration. Dual-GPU configurations won't present a problem, but for anything more than that you're going to want a Core i7-5930K or above.

Of course, you can't really ding Intel for doing this. The company will be offering a 6-core chip for hopefully under $400, and if you're interested in a multi-GPU setup that needs the extra PCI-Express lanes, you can probably afford the extra $200 for the upgrade to the Core i7-5930K anyway. Thus, if you're already playing around with the thought of acquiring a Haswell-E system with three or more GPUs, you'd better start adjusting your wishes or your budget.

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Niels Broekhuijsen
Niels Broekhuijsen

Niels Broekhuijsen is a Contributing Writer for Tom's Hardware US. He reviews cases, water cooling and pc builds.

33 Comments Comment from the forums
  • squirrelboy
    "and if you're interested in a multi-GPU setup that needs the extra PCI-Express lanes, you can probably afford the extra $200 for the upgrade to the Core i7-5930K anyway.

    No, cause you just spent all your money on a triple GPU setup ^^
    Reply
  • maroon1
    12MB L3 for i7-5820K ?

    All the other sources I read say that it has 15MB L3
    Reply
  • CaedenV
    I would love something like this for my next build! Get one of these in a little mATX box that can only fit one GPU and you would never miss the extra PCIe lanes. If Intel is going to continue focusing on performance per watt instead of increasing raw horsepower then the only way up will be to go after CPUs with more cores anyways.
    Reply
  • bluestar2k11
    I was planning to have the 4930k in my next computer for the coming year, but I think I'll throw this 5820 in instead^^ I want a CPU with 6 cores and HT, I figure it would last me like the next 5-7 years, with overclocking capability.

    And should games start being ported with greater CPU requirements from consoles threading, having 6 actual cores with 12 threads available should really help. I'm just not sure I'm sold on the DDR4... great speeds and bandwidth, but horrible timings. Might be able to be overclocked though... maybe... Will this CPU support quad channel memory like the 4930?
    Reply
  • dextermat
    Holding on my core i5-2500k for right now, will be waiting for 2nd generation with ddr4 support.

    They are just splitting hair in four here....
    Reply
  • SirKnobsworth
    Why would then not enable 8-8-8? 8 lanes should be plenty for any single GPU.
    Reply
  • lp231
    So those 12 PCIe lanes pieces of strings cost an extra $200?!

    Reply
  • oxiide
    So those 12 PCIe lanes cost an extra $200.
    This is already absurdly expensive hardware, considering how well the mainstream stuff performs. If you want to get the most for your money, you aren't looking at triple GPU setups anyway.
    Reply
  • Chris Droste
    im actually kinda surprised a vendor hasn't done a DDR3 x99 board. with most OC kits you'll get the same bandwidth and tighter timings, so the only real benefit comes down to voltage, but even then there's a few low-voltage DDR3 kits out there and if you're going multi-GPU, 6core, quad-channel memory, something tells me you're not going to flip out over 0.45v. sure there's x79 boards but are any of them reporting haswell-E support?
    Reply
  • lp231
    14009999 said:
    So those 12 PCIe lanes cost an extra $200.
    This is already absurdly expensive hardware, considering how well the mainstream stuff performs. If you want to get the most for your money, you aren't looking at triple GPU setups anyway.

    It's not about mutli GPU setups, some might need to install some other PCIe cards and when that is installed, does your PCIe lanes for your GPU still get reduced down to say from x16 to x8?
    Reply