Precision 7530 & Precision 7730 owner's thread

Discussion in 'Dell Latitude, Vostro, and Precision' started by Aaron44126, Jun 27, 2018.

  1. Martin Ro

    Martin Ro Notebook Enthusiast

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    Hm, I9s (at least the ones I checked like the the i9-8950HK) they have the same DMI setup like the i7's:
    https://en.wikichip.org/wiki/intel/core_i9/i9-8950hk
    and that's one of the i7's
    https://en.wikichip.org/wiki/intel/core_i7/i7-8850h

    According these pages, both have 4 Lanes with 8GT/s resulting in 4GB/s.

    even the i5 has the same setup ( https://en.wikichip.org/wiki/intel/core_i5/i5-8300h )
    and also the XEONS ( https://en.wikichip.org/wiki/intel/xeon_e/e-2186m )
     
  2. tem2

    tem2 Newbie

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    Are you sure? That seems really low/wrong. That means TB3 can't be anywhere near 40Gbps. In contrast, MacBooks seem to have 16 PCIe lanes and 1 or 2 TB controllers allowing full 40Gbps transfer rate. I checked Intel's specs and both the CPUs i7-8750H and i7-8850H have 16 max PCIe lanes, and the CM246 chipset has 24 max. So why does this computer only have 4? Did Dell have to strip out DMI links to save space or what?

    Thanks.
     
  3. baspacc

    baspacc Notebook Enthusiast

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    Dear TB18DC users,

    are you experiencing something like this:


    My external screen is connected to the dock via DP. The problem occurs only when the cable/connector is moved vertically (even a tap on the connector is sufficient). Occasionally (approx. once a week) the monitor can go blank for a second or so, but things get back to normal immediately. I contacted Dell and they suggested motherboard exchange. I don't want them to disassemble the device again, previous operations of this kind did aftect the machine already. Also, other USB-C devices using one of these ports do not seem to be affected (i.e. tapping does not result in the device being disconnected). BIOS (laptop, TB18DC) up-to-date. Drivers as well.

    Thanks!
     
  4. Ionising_Radiation

    Ionising_Radiation ?v = ve*ln(m0/m1)

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    I was referring to HEDT—high-end desktop. Check out the Core i9-9940X, for instance.

    Definitely not wrong. The DMI link is fixed, regardless of implementation, and Dell absolutely cannot mess with it.

    Let's clear up some misconceptions: the first 16 PCIe lanes are directly from the CPU, to any peripheral. This is typically entirely occupied by one single GPU. If you want SLI, you are limited to 2 × 8 lanes. And this is fixed for all consumer CPUs. HEDT CPUs like the 9940X or whatever are basically highly-binned Xeon parts, with correspondingly more PCIe lanes.

    Now, if you look at that graphic I posted, you'll see that the CM246 chipset itself is connected to the CPU by a DMI 3.0 link. Regardless of CM246, Z390, Z370, Z270, or whatever—they're all connected by the DMI link. This link is not really PCIe, but it has the bandwidth of 4 PCIe 3.0 lanes. See link below:

    https://www.anandtech.com/show/9483/intel-skylake-review-6700k-6600k-ddr4-ddr3-ipc-6th-generation/3

    Yes, the chipset exposes 24 lanes, but that's like 24 traffic lanes emerging from a tollbooth, into which go only 4.

    As for the implementation on MacBooks, they don't have very powerful GPUs in the first place, so what I think is done is that Apple can afford to allocate only 8 lanes to the GPU (this is typical in thinner notebooks), and use the other 8 to jack up the ThunderBolt controller(s).

    At any rate, 4× PCIe 3.0 lanes = 985 MB/s × 4 × 8 = 31.52 Gbps, which is only 9 Gbps short of the 40 achievable in TB3.

    What are you doing that needs to saturate that much bandwidth, though? I'm curious.
     
    Last edited: Mar 27, 2019
    tem2 and alittleteapot like this.
  5. Ionising_Radiation

    Ionising_Radiation ?v = ve*ln(m0/m1)

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    Furthermore, @Aaron44126, I am using driver 419.67, and haven't experienced BSODs—I am using the notebook in discrete GPU mode, exclusively. I haven't experienced any BSODs at all. Perhaps you'd consider getting a board replacement?

    Dell's QC on these machines really is terrible.
     
  6. Aaron44126

    Aaron44126 Notebook Prophet

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    Thing is, it is totally stable on 418.81 (three releases old at this point) and prior, only these 419.xx releases are giving me trouble, so I don't think that it's a hardware issue.
    I don't think that I can really complain to Dell unless one of their NVIDIA drivers has the problem...
     
  7. Ionising_Radiation

    Ionising_Radiation ?v = ve*ln(m0/m1)

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    Fair. Have you managed to pinpoint the cause of said BSODs? Maybe some sort of stack trace, or memory dump?
     
  8. Aaron44126

    Aaron44126 Notebook Prophet

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    I do have the memory dump but I honestly haven't spent much time digging into it at this point. (Too much other stuff to do...)
     
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  9. frostbytes

    frostbytes Notebook Consultant

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    Yes, I have the same issue with my 7730 and TB18DC. It's been that way since new. Even a very light touch on the connector seems to disconnect the dock.
     
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  10. Regular_Ragnor

    Regular_Ragnor Notebook Geek

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    Are those nvidia drivers you guys are talking about?...
    I can only find up to 411.63 published on the dell website and up to 416.78 on the nvidia website. Where are you getting those more recent drivers from?
     
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