XPS 13: Display issue affecting 7390, 9300 and 9310 models, XPS 15 models possibly affected as well

[Esokrates]

Disclaimer: The following report was first posted on Reddit here: https://www.reddit.com/r/Dell/comments/lj5qak/xps_13_display_issue_affecting_7390_9300_and_9310/
The following findings are published after being independently verified by other users of models 9310 (clamshell and 2-in-1), 7390 2-in-1, 9300. Please help me to spread awareness for this issue so that it gets attention by Dell.
If you happen to own such a device, no matter if clamshell or 2-in-1 variant, please check in your own interest whether your unit is affected too and leave a comment! Feedback from both, affected and not affected users is highly appreciated, but please make sure you explicitly tried the outlined steps to reproduce.
 

Short description of the issue:

When the machine is connected to AC without the battery being charged and CPU and RAM are stressed at the same time the display brightness starts to flicker. Turning off turbo boost or limiting cpu frequencies to 3.3Ghz makes the flickering go away. As a consequence the issue does not occur when running on battery because the cpu frequencies are limited there. Disconnecting AC power solves the issue instantly. The flickering can be very subtle as well as very noticeable and according to feedback I got from other users it may be more or less intense depending on the AC adapter you use.

This issue is not related to the operating system at all. It was reproduced across different 9310 2-in-1 units in Windows and Linux, as well as with the Diagnosis tool in the Bios (by running the ePSA memory test).
 

Steps to reproduce in Bios (ePSA):

The following steps to reproduce were tested on the 9310 2-in-1 and confirmed by other 9310 2-in-1 users, I have no feedback yet whether those steps to reproduce work as well for the 9300 and the 7390 2-in-1.

Ideal prerequisites: Make sure you are in a low light environment and the screen brightness is low. This is not a strict requirement, but makes the problem more apparent. Also your device should not be warm, as thermal throttling could make the issue unreliable / hard to reproduce.

1. Make sure Intel Turbo boost as well as Intel Speed Step are enabled on your device.
2. Make sure your machine is connected to the original 45W AC adapter and battery is not charging.
3. Start your Computer and press F12 to go into BIOS
4. Select "Diagnosis" and immediately press Esc to abort it
5. In the bottem left edge, select "Advanced Test"
6. Untick everything apart from "Memory test"
7. Start the test and watch out for display flickering. It can be very subtle at times, so watch closely, stop and start the test a few times if you don't see any flickering.
    

Steps to reproduce in Windows and Linux:

The following instructions may sound weird, but they are creating the perfect combination of cpu and memory utilization to trigger the flickering issue. Prime95's Large FFT stress test makes the display flicker as well in the first few seconds, but Google Chrome Webbrowser is better at triggering a workload where flickering occurs.

1. Make sure Intel Turbo boost as well as Intel Speed Step are enabled on your device and you do not have any energy saving power plan in place that limits turbo boost.
2. Make sure your machine is connected to the original 45W AC adapter and battery is not charging.
3. Install Google Chrome
4. Go to Settings / Advanced / System, untoggle "Use hardware acceleration when available" and relaunch Chrome
5. Go to Youtube and play a 4K video like this one here: https://www.youtube.com/watch?v=LXb3EKWsInQ
6. Set the video resolution to 4K (this increases memory and cpu usage and simulates a workload triggering the flickering)
7. Scroll down to the comments so that you have a mostly white display background
8. Observe the brightness of the display flashing / flickering.
    

Videos of the issue:

• Reproduction of the issue in Bios can be seen here: https://youtu.be/VGofdkQ7iU4
• Reproduction of the issue in Windows can be seen here: https://youtu.be/PeQfDFbaH3g
• Reproduction of the issue in Linux as well as the workaround limiting the cpu frequency to 3.3 Ghz can be seen here: https://youtu.be/bPtGS-1antE
   

Workaround:

Disable Turbo Boost in the Bios. If you are a Linux user, you can simply limit turbo boost to a maximum frequency of 3.3Ghz:

cpupower frequency-set -u 3.3GHz

Keep in mind, this is not persistent across reboots, so if you want to make this persistent place it in a startup script.
 

Models affected:

Please note: I have talked to most of the reddit users in this list to make sure they are indeed affected by the issue I described.

XPS 13 9310 2-in-1:

• I own that model (i7, 16GB, FHD, Manufacture Date: 12/04/2020). Got my second motherboard (Manufacture Date: 09/30/2020) already and I'm still affected.
• Reddit user u/FaSuu is affected: https://www.reddit.com/r/Dell/comments/la7lu1/new_2020_xps_13_2in1_after_3_weeks/gm3cvji/?context=3
• Reddit user u/kaiser1025 is affected, got screen and motherboard replaced and still has the issue. Was so kind to confirm both the issue and the workaround.
• Reddit user u/aleksfadini was so kind to confirm both the issue and the workaround.

XPS 13 7390 2-in-1:

• Reddit user u/Taylen137 has this issue, got the screen replaced as well as a replacement unit, all of no avail: https://www.reddit.com/r/Dell/comments/ifegy0/xps_13_7390_2in1_slight_screen_flickering_when/
• Reddit user u/frustatedclient11 is affected: https://www.reddit.com/r/Dell/comments/kwm8wa/review_xps_13_2in1big_buck_little_bang/
• Reddit user u/Firejay112 is affected and goth both screen and motherboard replaced, which didn't help: https://www.reddit.com/r/Dell/comments/kwm8wa/review_xps_13_2in1big_buck_little_bang/gjabism?utm_source=share&utm_medium=web2x&context=3
• Dell forum user "e19y82" has this problem: https://www.dell.com/community/XPS/Bug-Report-XPS-9300-screen-brightness-blink-flicker/m-p/7782999/highlight/true#M76816

XPS 13 9310:

• Dell forum user "ce123" (Reddit user u/undostres123) reports to be affected here: https://www.dell.com/community/XPS/Bug-Report-XPS-9300-screen-brightness-blink-flicker/m-p/7805687/highlight/true#M78802 and here: https://www.reddit.com/r/Dell/comments/kwm8wa/review_xps_13_2in1big_buck_little_bang/gmz1ufc?utm_source=share&utm_medium=web2x&context=3

XPS 13 9300:

• A real life acquaintance owns a XPS 13 9300 (i7, 16GB, FHD, Manufacture Date 01/02/2020) and never noticed any flickering, however I was able to trigger it by running a stress test and the steps to reproduce in chrome at the same time. It is quite hard to get that machine to boost to high frequencies but the flickering is there as soon as the frequencies are reached.
• Dell forum user "zrs5532" had this problem, got screen and motherboard replaced and finally got a replacement unit and nothing helped: https://www.dell.com/community/XPS/Bug-Report-XPS-9300-screen-brightness-blink-flicker/td-p/7640763
• Dell forum users "manylander" and "TrueNorth17" also have this problem, see the same link as above.
• Youtube user "R Z" had this issue on his 9300 as well, see his comment under the video here: https://www.youtube.com/watch?v=FKRyV1ly1dg
   

Analysis:

The evidence so far suggests that all 9310 2-in-1 units as well as all 7390 2-in-1 units are affected by this issue (both FHD+ and 4K panels).

Thanks to all the Reddit users who were so kind to verify the issue in a personal chat: u/aleksfadini, u/FaSuu, u/kaiser1025, u/Tylen137, u/Firejay112.

[JLuke420]

I have an XPS 13 9310 with a 4K screen with the same problem. on or off the charger if HDR is on. a flicker begins. I have tried everything and just came to the conclusion the screens are messed up from the factory. hopefully, this thread will make dell put out a recall on these screens. it's a useless feature for most. but for the price we are paying everything should work as advertised.