Dell Precision 7540 and 7740 Owner's Thread

Discussion in 'Dell Latitude, Vostro, and Precision' started by djdigitalhi, Aug 13, 2019.

  1. Hopper82

    Hopper82 Notebook Geek

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    Understood.
    Anyway, mine should be on delivery this monday, I would do cpu repaste and make some test to see where is the cpu limit.
     
  2. reburns

    reburns Notebook Guru

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  3. Aaron44126

    Aaron44126 Notebook Prophet

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    There are no overclocking settings in the BIOS (or any settings related to memory, really). You get what the system selects at boot time and that's that.

    In the Precision 7730, users had mixed results using memory faster than the spec'ed DDR4-2666. (It worked for some, others got strange behavior and/or BSOD; sometimes BIOS updates would change the behavior for better or worse.)

    Dell is supposedly going to start supporting DDR4-3200 in the Precision 7740 soon. There may be a BIOS update to handle this before they start actually selling them. I personally would either grab 2666 modules (taking latency into account, the actual speed difference will be rather negligible), i.e. these or maybe these which have lower latency; or, wait until we hear some feedback from users trying 3200.
     
    Last edited: Aug 21, 2019
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  4. reburns

    reburns Notebook Guru

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    Thanks! The two fastest 16GB modules appear to me to be:
    HyperX 15-17-17/2666
    GSkill 16-18-18/3000 = 5.5% - 6% faster? Is that a worthy number or just asking for trouble?

    The new laptop won't arrive until ~ Sept 9th, so who knows, maybe we'll see the BIOS update by then? Does that even make sense since the i9-9980HK processor spec sheet says 2666MHz - might that clock rate update apply to a different processor?
     
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  5. Aaron44126

    Aaron44126 Notebook Prophet

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    There have been many cases of memory better than the Dell spec working in the Precision systems. The memory controller is in the CPU so you can just check Intel Ark and see what the CPU supports. However, there are cases when it doesn't work out so well (see last gen 7730 and DDR4-3200 as I mentioned). We don't really know until someone tries it and reports back.
     
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  6. Hopper82

    Hopper82 Notebook Geek

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    Ok, finally on tuesday I got my new 7740 with i9 9980HK and no discrete graphics (some days before the expeted 27/08 delivery date, some points more for Dell).

    Some thoughts after 2 days of test:

    The materials, general build quality and the looks are Ok. It seems what it should: a workstation level notebook.
    The FHD ips screen is also quite good at first look, I don't alredy use it under direct sun light but it seems bright enough with good color deep and contrast.
    All around a well-presented product.

    Service side: its quite easy to have access to all the parts of the notebook. In 20 minutes (the first time) I got heatsink off (using service manual).
    Some parts could be a little more sturdy, but overall is a good layout (not as good as the HP, for example, that is totally tool-free in the bottom-cover part).

    No problem putting in place the upgrades: 4x16gb HyperX 2666 cl15 (a bargin at 280$ for 64gb on Amazon WD), 2Tb 970 Evo Plus in place of the original Micron nvme 256Gb (meh).

    Now the 'bad' part: thermal is simply inadequate for this kind of rig. And not for a project lack, but just because the heatsink is CHEAP.
    You don't need to be a 10 years experienced engineer to see that with a 2-3mm of extra tickness in the copper plate, a good mirror-finished contact suface and a good thermal paste (not alike the original hardened toothpaste) there will be at least 20°c of difference in heavy workload temperature.
    I would had pay 50$ more with no problem at all to have this kind of solution instead of the original messy one.

    Now, I made the repaste using AS Mx-4 and thermal grizzly pads (for the VRM part) and play half a day with XTU to find out the best solution against clock/undervoltage, but for me is still a not satisfactory situation.
    The 9980HK is surely a little beast and a heat-generator, but not as much as you can aspect from a 5Ghz capable cpu. So it's only a producer willing to devolop or not a good thermal platform to support it, and to be mischievous you could think that is not in Dell's (or any other volume-producer) interest to unleash the full power of a cpu that probably could last minimum 5 five years from now.

    Some numbers:
    with the original solution the cpu hit easly 100c (and thermal throttling obviously) already in windows 'normal task'.

    The cinebench R20 result in this conditions was from 3300 to 3500 pts depending on the current thermal status when launched, this mean a 3 to 3.3ghz all core turbo speed instead of the 4.2ghz as from spec (without thermal throttling). So you lost about 25-30% of cpu performance just for thermal problems. And keep in mind that I decided to go for a system without discrete graphics just to have more heat-room in the heatsink (and that's it, since the VGA part is free but present). Also, Dell's choose to limit the turbo power at 75W instead of 90W that should be normal pool size for this cpu (maybe because it's easier than made a well designed heatsink).

    This is instead the result after the repaste and the tuning:

    ThrottleStop Setting [edited after dismiss XTU]:
    cpu/cache -116mV offset
    System Agent + 75mV offset (default is +70mV)
    IccMax Cpu 180A (not sure that is fully usable)
    Short Turbo TDP Max 110W (not sure that is fully usable)
    Long Turbo TDP Max 150W (not sure that is fully usable)

    Turbo mode
    1 core 51x
    2 core 50x
    3 core 49x
    4 core 48x
    5 core 46x
    6 core 45x
    7 core 44x
    8 core 43x

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    The 9980HK stays in the 3.8-4Ghz zone even on heavy 100% MT activity, with full fans speed and 95-100°c temperature. In normal windows use it stays in the 4.7 to 5.1ghz area from 50 to 75°c (depending on tasks), with the fans almost always at low speed. Not a bad result, anyway.

    The 970 Evo Plus is fast as it should, mark approximatly an average of 350k iops in all around use. But again, the original heatsink for the M2 drives is better than nothing but should be easly made better (some heat-wings and some more materials would cost just some cents more), and on heavy use the drive start throttling reducing the speed.

    [​IMG]

    [​IMG]

    In the next days I'll try to order a new heatsink since I see that there's another version with one more heatpipe (I don't know why).

    This is mine:
    [​IMG]

    This is the one I would try:

    [​IMG]

    I will report if the situation will be better with the other heatsink.

    In conclusion:
    The 7740 could be a great mobile WS. But.. with the original thermal solution you simply can't use the new 8 core processor at 100% speed. Maybe just 60-70% in heavy MT scenarios.
    The 9980HK is capable of doing 4.7-4.8Ghz ALL CORE with just -100mv and ~90W of tdp, a little beast, as you can also check in some other gaming systems:
    https://www.ultrabookreview.com/27215-asus-rog-g703gx-review/

    I really hope that in the next months also some WS producer can understand that is important to have the possibility to use full power also on work scenarios, since it's really NOT impossibile to have a good heatsink without a bulky case.
     
    Last edited: Aug 24, 2019
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  7. Ionising_Radiation

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

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    That extra heatpipe is for the GPU.
     
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  8. Hopper82

    Hopper82 Notebook Geek

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    Yeah, but maybe it would help to drain heat also on the cpu part (especially in my case where there's no GPU at all).
     
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  9. Aaron44126

    Aaron44126 Notebook Prophet

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    Doubtful. There is no connection between the extra heatpipe and the CPU (it is mounted squarely on the GPU part of the heatsink). But you could certainly try it...
     
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  10. Don Patrone

    Don Patrone Notebook Enthusiast

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    I will order a Precision 7740
    But i dont know, should i take a xeon or the normal i9.
    With the xeon i can use the Ecc Ram, but is it worth it?
    I use the Workstation for Hobby (Video, 3D) and Gaming.

    I want to upgrade the ram to 64GB (4x16)
    Which Ram should i buy, which is the best for this Workstation?
     
    Last edited: Aug 22, 2019
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