Dell Precision 7540 and 7740 Owner's Thread

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

  1. n0xlf

    n0xlf Notebook Enthusiast

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    Has anyone experienced (or solved) the display flickering problem on the 7740 with the 4k display? It's similar to this issue: https://www.dell.com/community/XPS/Precision-7730-display-lined-flickering-in-BIOS/td-p/6219020

    I have tried literally every version of Intel UHD 630 driver and BIOS revisions, including from Intel's site, all without success. Certain versions allow you to disable display panel self refreshing, but that didn't fix it. There is a Linux bug mentioned that is similar to this problem where setting a certain eDP mode caused it (https://unix.stackexchange.com/ques...after-upgrade-to-kernel-5-x-on-dell-xps-15-95) but that obviously won't translate to Windows easily.

    The problem survives reboots and occurs in the BIOS. The only "progress" I've made is pulling the battery connector for an extended period of time which restores the display refresh, but only very temporarily during boot. Once it's back in Windows, it's bad again.
     
  2. Aaron44126

    Aaron44126 Notebook Prophet

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    If it occurs in the BIOS, you need to call Dell and have them replace whatever the problem piece of hardware is. (Display panel? Display cable? Motherboard?)
     
  3. n0xlf

    n0xlf Notebook Enthusiast

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    It's probably not a hardware problem so I haven't even tried to contact Dell. This seems to occur either in the panel itself or in the internal displayport interface where certain power saving options get set, which is why it survives a reboot but not a battery disconnect.
     
  4. jack574

    jack574 Notebook Consultant

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    Thanks!
     
  5. mr_handy

    mr_handy Notebook Evangelist

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    Hi all -- about to be joining the 7540 team as well. Not at all new to Dell but the last full-size Precision I used was an M4700 we evaluated for work back in I think 2012-2013? Getting the i9-9880HK and RTX 3000 off outlet -- had actually been thinking to of going with the Lenovo X1 Extreme/P1 Gen 2 for this generation but they never dropped in price enough or showed up on their Outlet in a spec I wanted.

    Not looking forward to the offset keyboard/10-key, but otherwise really looking forward to it -- even with Quadro vs. Geforce differences this should be a pretty huge jump from my present "gaming" laptop (a 9560 - throttle-heavy 1050), and the longer keyboard travel will be nice bump as well. I realize that with thermals the jump from my work laptop (Latitude 5491, i7-8850H) is going to be less huge than two more cores and the published clock difference will indicate, but it should be at least as capable and the i7-7700H to i7-8850H jump was pretty huge for when I work from home.

    Will be dual boot Windows (for gaming and general personal use) and Linux (for Java dev work so I can leave my work notebook at the office.) Am dropping in a Corsair MP510 960GB and am leaning towards just using the stock 256GB drive for Linux and keeping the two OSes entirely segregated by drive.

    Main question:
    I haven't seen any references to using these with a 130W external supply. My recollection was tthat the M4700 throttled to near useless (IIRC locked at 800mhz) on 130W. How does this one do?

    I understand these can pretty much run to the full 180W with a heavy CPU+GPU load, but how about CPU-only loads? I've got several of the 130W supplies (PA-4E from memory) from the E-docks (and two WD15s that deliver 130W) and would love to be able to use them as spares even if limited in how much I can use it, just not if it's a hard lock at 800mhz.

    How about 90W for auto/air use?

    A few others:
    1) Is ThrottleStop really a necessity, or is Intel XTU adequate for undervolting on WIndows? The i7-7700H in the 9560 has never been very happy with underclocking either with XTU or under Linux, and my 8th-gen systems (both iGPU-only Latitudes) are only performance-critical on Linux [and the work-provided 5491 doesn't even have Windows on it.]

    2) I've always in the past wiped and reinstalled Windows as soon as I got the system. Is there any reason not to do that on here? I've set up a few lower-end machines recently where I didn't bother, and there's less Dell crapware than there used to be (and sadly, more from MS itself.) Is there anything Precision-specific in terms of drivers that isn't easy to reinstall? Is there any value in Precision Optimizer when I'll be using the dGPU when in Windows basically purely for gaming?

    3) Panel lists on the packing list as "MOD,LCD,FHD,1.3,NTCH,AUO,7540" -- is this a sign I lost the panel lottery? The AUO in my 5491 is pretty terrible.

    4) What's the best way to turn off the dGPU entirely for use under Linux? I used to use Bumblebee on the 9560 before I gave up on Linux on there. If it matters, I'm mostly a Gentoo user and pretty much self-supporting, but my experience with Optimus+Linux on the M3800 and 9560 has been terrible.

    Thanks much to everyone up-thread, there's been a lot of really useful information. With 60+ pages I may have missed some of the answers above, apologies if so.
     
  6. Aaron44126

    Aaron44126 Notebook Prophet

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    The system still throttles significantly with a power supply less than 180W. AFAIK it has not really improved in this area since the M4700 era. Obviously Dell could improve this somewhat if they wanted to, but Dell ships it with a 180W PSU and doesn't expect you to be using anything lower.

    You can use a 180W PSU on an airplane even though they cap out at around 100W. You will have to plug and unplug it a few times in order for the capacitors to charge up and then it should be fine, operating at less than 100W as long as you don't put it under heavy load.

    You can undervolt with either ThrottleStop or Intel XTU. (Don't try to use both at the same time.) I haven't mess with this too much but I think that ThrottleStop is better if you want the undervolt profile to be loaded automatically at startup.

    Reinstalling Windows is fine. (I always do this.) Note that you have to install the Intel Serial I/O driver before the touchpad will work. (Not exactly obvious.) Other than that, you can install either the Ethernet or Wi-Fi driver and get the system online, and then run Windows Update one time and it will pull down almost all of the drivers that you need by itself. Install the Thunderbolt stuff (driver+firmware) from Dell and the latest BIOS update.
     
  7. win32asmguy

    win32asmguy Moderator Moderator

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    If you do not need the nVidia GPU at all under linux, I have found the best method is to write udev rules to disable the extra nvidia PCI functions (audio controller, usb-c controller, type-c usci), then make a custom build of bbswitch source based on the pm-rework branch, with a couple of changes putting the card into d3cold instead of d3hot. It seems to be stable across sleep / resume / multiple calls to lspci. Also you may need to override acpi_osi to not include "Linux-Dell-Video" so the card can properly be put into d3cold power state.
     
  8. SvenC

    SvenC Notebook Evangelist

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    On Windows I used ThrottleStop with 90W and 130W on m6500 and m6800 when travelling and was able to stop the throttling. The 90W from an old Inspiron got quite hot. The 130W was pretty OK. Only CPU based work, no GPU intense tasks. I guess that should work for the 7xx0 Precisions as well.

    I don't know if such a tool exists on Linux as well.
     
  9. TunaDog

    TunaDog Notebook Enthusiast

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    When I flattened my 7740 in November and installed Windows 1909 the touchpad Just Worked, so apparently Dell finally managed to get some version of that serial driver baked into the Windows distribution. But I would still recommend downloading all the drivers from Dell and putting them on a USB stick so that you have them handy when installing the OS. A lot of the drivers from Dell weren't needed: once you get networking going Windows will pull down many drivers on its own.

    One thing I appreciate in the BIOS is that you can disable a drive so that its not visible to the OS. So my data, and my Dell driver kit, is on D:, and when I do OS install I hide it. Then re-enable once the windows installer has formatted and installed on C:.

    Another thing about that: the BIOS insists on reporting any SATA SSDs before NVMe. In my laptop boot is NVMe and D: is a SATA SSD. By hiding D: from the windows installer the boot files are stored on c: where I want them. Whereas if I had left the SATA drive visible the boot loader would have been installed on D:.

    You could of course achieve the same thing by physically pulling the drive, but I appreciated not having to open the laptop.
     
    Last edited: Jan 20, 2020
  10. feudalkaos

    feudalkaos Newbie

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    I am purchasing a 7740 with the 1920x1080 display that says it is WWAN compatible. It does not come with the WWAN card.

    I am trying to find out if the machine will include the antenna and SIM card holder even though it did not come with a WWAN card. I want to put in a DW5811E card and am trying to find out if everything is there but the card.

    Can someone with the LCD Back Cover (Non-Touch Screen), WLAN/WWAN Capable and 17.3 inch UltraSharp FHD (1920x1080) Anti-Glare IPS 100% sRGB Non-Touch Display and without a WWAN card, open their back cover and tell me if they have the extra antenna for the WWAN near the WWAN slot and if the SIM card holder is intact with the small silver cover on it?

    Thank you!
     
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