Thank you for the solution, it was necessary to switch USB from USB 3 to USB 2 in the monitor menu. The resolution now works 3440x1440 @ 100Hz. Great. Thank you jphughan!
@Dandys One thing I forgot to mention when writing the post above. The XPS 13 9350 has a known issue that causes it not to be able to send video over a USB-C to USB-C cable when used with Dell USB-C displays. That known issue is documented here. I also found by testing my own XPS 13 9350 that it won't send video over USB-C to a Lenovo ThinkPad USB-C dock. So there may be other non-Dell equipment where this problem occurs even if Dell's own testing did not encounter them and therefore their knowledgebase article about the issue does not mention them. However, one option in that case would be to use a USB-C to DisplayPort cable instead. That seems to work consistently on the XPS 13 9350 even for Dell displays that don't work over USB-C to USB-C. The drawback of course is that you would not be able to get any USB data or power from the display using that type of cable.
@Dandys The XPS 13 9350 supports DisplayPort 1.2/HBR2 over USB-C, not the newer 1.4/HBR3 standard. However, DP 1.2 is sufficient to run 4K 60 Hz, and 3440x1440 100 Hz requires slightly LESS bandwidth than that. So it should be fine. Note however that in order to get a full-bandwidth DisplayPort link on a USB-C to USB-C connection, the USB data speeds have to be limited to USB 2.0. Some displays with built-in USB ports instead configure the USB-C link to support video and USB 3.x data speeds, but supporting USB 3.x requires cutting bandwidth in half, and a half-bandwidth link of DP 1.2 would definitely NOT be sufficient for 3440x1440 100 Hz. So make sure your display either does not have built-in USB ports or offers an option to customize how it configures the USB-C link. On some Dell displays that support this, that option is called USB-C Prioritization, for example. That option exists because depending on whether the system you'll be using supports DP 1.2 or DP 1.4 and depending on whether you plan to attach a second display via daisy chaining, you might want or need a full-bandwidth video link and only USB 2.0, or you might be able to run the desired display setup using only a half-bandwidth video link and then get the benefit of having USB 3.x as well.
Dandys
2 Posts
0
May 25th, 2021 13:00
Thank you for the solution, it was necessary to switch USB from USB 3 to USB 2 in the monitor menu. The resolution now works 3440x1440 @ 100Hz. Great. Thank you jphughan!
jphughan
9 Legend
9 Legend
•
14K Posts
0
May 25th, 2021 08:00
@Dandys One thing I forgot to mention when writing the post above. The XPS 13 9350 has a known issue that causes it not to be able to send video over a USB-C to USB-C cable when used with Dell USB-C displays. That known issue is documented here. I also found by testing my own XPS 13 9350 that it won't send video over USB-C to a Lenovo ThinkPad USB-C dock. So there may be other non-Dell equipment where this problem occurs even if Dell's own testing did not encounter them and therefore their knowledgebase article about the issue does not mention them. However, one option in that case would be to use a USB-C to DisplayPort cable instead. That seems to work consistently on the XPS 13 9350 even for Dell displays that don't work over USB-C to USB-C. The drawback of course is that you would not be able to get any USB data or power from the display using that type of cable.
jphughan
9 Legend
9 Legend
•
14K Posts
0
May 25th, 2021 08:00
@Dandys The XPS 13 9350 supports DisplayPort 1.2/HBR2 over USB-C, not the newer 1.4/HBR3 standard. However, DP 1.2 is sufficient to run 4K 60 Hz, and 3440x1440 100 Hz requires slightly LESS bandwidth than that. So it should be fine. Note however that in order to get a full-bandwidth DisplayPort link on a USB-C to USB-C connection, the USB data speeds have to be limited to USB 2.0. Some displays with built-in USB ports instead configure the USB-C link to support video and USB 3.x data speeds, but supporting USB 3.x requires cutting bandwidth in half, and a half-bandwidth link of DP 1.2 would definitely NOT be sufficient for 3440x1440 100 Hz. So make sure your display either does not have built-in USB ports or offers an option to customize how it configures the USB-C link. On some Dell displays that support this, that option is called USB-C Prioritization, for example. That option exists because depending on whether the system you'll be using supports DP 1.2 or DP 1.4 and depending on whether you plan to attach a second display via daisy chaining, you might want or need a full-bandwidth video link and only USB 2.0, or you might be able to run the desired display setup using only a half-bandwidth video link and then get the benefit of having USB 3.x as well.