Latitude 5401 or Precision 3541 for CPU intensive work

Discussion in 'Dell Latitude, Vostro, and Precision' started by karmakuma, Jan 21, 2020.

  1. karmakuma

    karmakuma Newbie

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    Hi
    I'm new to this forum and am seeking decision advice between the above two systems.

    The use case predicts workload with high demands for CPU, scaling well from 4-6 cores. Tests have shown that internal GPU vs. dedicated GPU do not make any real difference performance wise.

    Which of the two systems, Latitude 5401 or Precision 3541 do you think will cope better with overall system heat to keep core clock speeds as high as possible on long compute runs, avoiding aggressive heat based CPU throttling as good as possible...?

    Latitude:
    14 inch, 68wh battery, i7-9850h, 32GB Memory, 1TB NVME, no dedicated GPU (only intel UHD 630)

    Precision:
    15 inch, 97wh battery, i7-9850h, 32GB Memory, 1TB NVME, dedicated Nvidia P620 + Intel UHD 630 GPUs

    Both systems are platform derivatives: Latitude 5400/5401/5500/5501 as well as Precision 3540/3541. They all share the same motherboard design, chassis layout, and, apparently cooling design. CPU and GPU share the same cooling circuit.

    Only major differences being 14 vs 15 inch, 68wh vs 97wh battery and consumer vs prosumer dedicated GPU (partially optional, depending on base config).

    Thoughts:
    15 inch Precision:
    Positive: CPU does generate a little less local/on-die heat from onboard GPU since heavier graphics tasks will be offloaded to the dedicated GPU. Has a bit more room (in theory less cramped internally, but not sure if this helps).
    Negative: Has a dedicated GPU which will generate a little added heat to the shared cooling design, even when idling and the system is running all graphics tasks off the integrated GPU.

    14 inch Latitude:
    Positive: No dedicated GPU that could generate additional heat under any circumstances.
    Negative: In theory a little more cramped internally since only 14 inch chassis, CPU could generate a bit more local/on-die heat since any and all graphics calculations will be done from onboard GPU.

    Does any of the above may any difference at all, since CPU and GPU are sharing the same cooling system? What do you think? Any input is highly welcome :)
     
  2. Aaron44126

    Aaron44126 Notebook Prophet

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    If graphics switching is working properly, the discrete GPU is powered off when it is not needed and does not generate any extra heat.
     
  3. karmakuma

    karmakuma Newbie

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    Is that so? I did not know this. Thats good news! I assumed that discrete GPUs would "at best" go into their deepest power saving mode. But not power off/down completely. That's good news! Can you tell me what you understand under "working properly"? Would a Precision 3541 with its Intel UMA 630 and Nvidia Quadro P620 combination support this?
     
  4. Aaron44126

    Aaron44126 Notebook Prophet

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    Basically any modern Intel+NVIDIA combination should work for graphics switching.
    Couple of things on why it might not behave right.

    1. With an NVIDIA GPU, you can check the discrete GPU status this way. Go to the NVIDIA control panel, and select "Desktop → Display GPU activity icon in notification area" from the menu at the top. An icon will appear in the notification area / system tray. If it is colored, the GPU is powered on. If it is gray/black, the GPU is powered off. You can click on the icon and a window will open showing which programs are running that are using the discrete GPU.

    It is possible for background tasks to latch onto the GPU and keep it powered on even when there is no real need for it. You can check by clicking the notification tray icon as described above. An example I have that is consumer and not pro related is the Epic Games launcher — a game client similar to Steam that just hangs out in the background to update games and handle launching them. It has basically no reason to use the dGPU at all, but if it is running, it keeps the dGPU powered on, even while totally hidden or minimized. (I have complained to them about this and ... maybe they will fix it someday was basically the response that I got.)

    2. Some systems don't seem to be powering off the dGPU properly. We have complaints regarding the Precision 7X30 and 7X40 systems, in which the dGPU seems to not go to "sleep" even when nothing is using it and it is showing gray/black in the notification area. It continues to draw around 5W. People have found ways to get it to go to sleep — running certain Adobe apps and leaving them minimized seems to do the trick, for example, Adobe must send some command to the dGPU and tell it to sleep. The Precision 5530/5540 and newer XPS 15 systems do not have this problem and power off the dGPU properly without a fuss, so it is a mystery. I'm not sure if any other Dell systems are affected.
     
    Last edited: Jan 21, 2020
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  5. karmakuma

    karmakuma Newbie

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    Aaron, thanks a lot for your effort in bringing light into the dark! What a great writeup!

    The case is clear for me, it will be the Precision 3541. Even more so, since I just read through the official Dell Service manuals for both systems. When ordering with a dGPU, the Precision 3541 comes equipped with two heat pipes covering dGPU and CPU in a shared circuit (connecting to a shared single fan and fin base, but still), whereas the 5401 does not (only one heat pipe covering dGPU and CPU connecting to a single fan and fin base). Only its bigger sibling, the 5501 which is technically a Precision 3541 with some lesser display, consumer/MX clas dGPU and smaller battery has the dual heat pipe circuit.

    Again, thanks a lot!

    Case closed :)
     
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