@T_P The fact that Dell makes a system that requires something doesn't mean that every accessory they make will support the requirements of that system. It also works the other way. For example, Dell makes displays that use Thunderbolt for full functionality, and they also make systems that don't support Thunderbolt, which wouldn't be able to use that display to its maximum potential. (That said, I do find it a bit strange that the first XPS 15 to run 130W over USB-C was introduced in late 2015, and here we are in late 2021, and Dell still hasn't made any USB-C display that provides 130W.)
In terms of your options, they are correct. In terms of the questions:
To check power, go into the BIOS Setup and check either the system summary or battery information section. One of those areas should show the identified wattage of the attached power source.
In the dock scenario, you could use either the USB-C or downstream TB3 port to connect the U2722DE. Or you could use a regular DP cable for video and also connect a USB-C to USB-A cable for USB 3.x data (USB-C side plugged into the USB-C input on the display, USB-A side connected to the WD19TB). That cable should have been included with the U2722DE.
In terms of resolution, first of all I realized I made a mistake earlier. I thought the U2715H was a 1080p display, because these days Dell uses "H" for 1080p and "D" for QHD. But I'd forgotten that back in the days of the U2715H, they used "H" for 16:9 displays in general, including those with QHD. So your bandwidth situation was even worse than I realized in the USB-C scenario! Anyway, the dock's DP outputs only support DP 1.4 if the source system does. But that's not an issue because you don't need DP 1.4 for your display setup. A single full DP 1.2 interface is enough to run 4K 60 Hz, in fact a single interface can run dual QHD on its own. The problem in your USB-C setup is that you only have half of a DP 1.2 interface since you're also running USB 3.x. But when your system is using Thunderbolt, it can run two full DP 1.2 interfaces and USB 3.x all simultaneously. So yes, you'll have enough bandwidth for dual QHD, in fact you'd have enough for triple QHD or dual 4K 60 Hz.
@T_P The bad news is that this isn't going to be a good setup.
The reason you're having an issue is that the XPS 15 9500 is a DisplayPort 1.2/HBR2 system, not a DisplayPort 1.4/HBR3 system. HBR2 offers less video bandwidth than HBR3. A full DP 1.2/HBR2 link would be enough to run QHD (2560x1440) and FHD (1920x1080), but the U2722DE is configuring the USB-C link to run both video and USB 3.x data. Running USB 3.x data cuts video bandwidth in half, and half of a DP 1.2/HBR2 link is only enough for a single QHD display at the standard 60 Hz refresh rate. You don't have enough bandwidth to run an FHD 60 Hz display in addition to that. The U2722DE does have a USB-C Prioritization option that can be used to have the display configure the USB-C link for full video bandwidth, but that will drop USB 3.x data speeds down to USB 2.0, which will bottleneck your Ethernet connection and any USB 3.x peripherals you have connected to the display. If you had an HBR3 system, you would be able to run QHD+FHD -- actually even QHD+QHD -- and USB 3.x simultaneously over USB-C, but your system doesn't support that.
The additional possible issue you might want to be aware of here is that the U2722DE only provides up to 90W of power. The XPS 15 9500 can only function optimally on 90W if it has ONLY an Intel GPU. If your system has an NVIDIA GPU, then it would be designed for a 130W power source, and therefore running it from a 90W power source may result in slower battery charging and/or reduced performance, especially when using the NVIDIA GPU.
The only way to get your two displays and USB 3.x data and enough power to run your system properly all over a single cable would be to use a Dell Thunderbolt dock like the WD19TBS. If you don't want to do that, then for power you may want to consider connecting the system's power adapter directly. It's completely fine to have that power source and a USB-C display that supports power delivery connected simultaneously. Your system would choose the higher wattage power source and ignore the other; it won't cause any damage. And then in order to get your displays working properly, you'd have to choose one of these options:
Set USB-C Prioritization on the U2722DE to High Resolution and accept USB 2.0 data speeds, including reduced Ethernet performance.
Connect the U2715H directly to your system rather than using a daisy chain, using a USB-C to DisplayPort cable. This will allow both displays to run at their native resolutions and refresh rates AND maintain USB 3.x data connectivity to the U2722DE, but you'll have a second cable to connect. And if you also had the system power adapter connected, that would be three total cables.
Wow. Thank you for your time jphughan. Your detailed post helped me understand the situation. Though, I'm so disappointed... I indeed have a Nvidia GPU.
First, what is making me upset is that I asked Dell representative if the U2722DE docking station was able to power up my laptop. I wouldn't have bought this more expensive monitor. Two USB-C cable is one thing as XPS15 has 2 ports on the left side. But 3... grrrrr.
Questions: - Is the DisplayPort version (1.2 vs 1.4) hardware or software related? Graphic card related? - In the scenario I connect the U2715H directly to the XPS via a USBC to DisplayPort cable, as the U2715H don't have a built in docking station, would the power delivered from the monitor be enough for the XPS (135W)? Or is a USBC splitter could do the job, one for the Displayport cable and one for the power supply? - Is there a 27" monitor with a usb-c connector that could power up 135W?
@T_P Happy to help, although I wish I'd had better news for you. To answer your follow-up questions:
The DP version is determined by the capabilities of the hardware involved. In your case, the XPS 15's display outputs are all wired to the Intel GPU, and the Intel GPU built into that generation of CPU only supports HBR2. (The NVIDIA GPU is not wired to any outputs and instead operates only when needed and only as a rendering platform, which then passes completed video frames through the Intel GPU for output. This technology is called NVIDIA Optimus, and it's implemented for battery life reasons, because it allows the NVIDIA GPU to shut down when its performance isn't needed.)
Connecting the U2715H directly to your display won't change anything about the power you receive from the U2722DE. You're not "losing" power from the U2722DE by having the U2715H attached to it. The U2722DE simply only supports 90W output to an attached system. That might be based on the sizing of its built-in power supply.
There are splitters that give you a DisplayPort output and a USB-C power input, but I'm not sure they would work. The reason is that the formal USB PD spec maxes out at 100W. Dell did something proprietary to stretch that out to 130W (not 135W), and they implemented support for running 130W over USB-C/TB3 on some of their docks and systems, including your XPS 15 9500, but you won't find that support implemented on third party products. The USB PD spec was very recently revised to support up to 240W, but the only product on the market that actually supports that is Apple's 140W USB-C charger, and then only when used with their proprietary MagSafe cable. There aren't any USB-C cables that support that new spec yet, and your system was created before that standard existed anyway. But if you want to try a splitter just to see if maybe you can get your power adapter's full 130W through it even if that isn't technically supported, here is the right type of adapter from a manufacturer that I have had consistently good luck with. I guess worst case you could return it, but if it works, then it's a simple and inexpensive way to run both displays, with USB 3.x connectivity to the U2722DE, and optimal power for your system all through two cable connections, thereby keeping one port on your system free.
In terms of displays that support 130W output, again since that's a proprietary Dell implementation, it would have to be a Dell display, and I haven't seen any Dell displays support that level of power output, not even their very expensive displays.
Crystal clear! Thank you again for your explanation. As the "130W" is a Dell design, it's difficult to understand the reason why the U2722DE can't provide 130W?! Anyway, for a summary, my options are: 1- Connect 3 cables (1 for U2722DE, 1 for U2715H and 1 for power) 2- Connect 2 cables (1 for U2722DE, 1 for U2715H and power with a splitter usb-c/DisplayPort) but to be confirmed if that deliver enough power 3- Connect 1 cable but buy a WD19TBS dock. Plug both monitors, ethernet and usb3 peripherals in it.
New questions: - in the scenario 2, how do I know if there's enough power going into the XPS? - in the scenario 3, I will have to plug the U2722DE in the USB-C Multifunction DisplayPort? I guess yes if I want to use USB3 peripherals with it? - also in the scenario 3, I will have to plug the U2715H in the DisplayPort 1.4? With that setup, both monitors will be QHD even if my XPS has a displayport 1.2? Thank you so much again for your time!
For the sake of posterity, I wanted to note that solution 2 does not work. The cable Matters (usb-c/DisplayPort splitter) mentionned does not provide 130W, only the specified 100W.
@T_P Thanks for reporting back. Bummer that you couldn't get 130W through the adapter, although I figured that would be a long shot. Dell's 130W implementation is proprietary. I thought it just might manage to get through that device, but apparently not. Good to know though!
I finally received my WD19TBS. Here's the way I connected everything:
- Keyboard, mouse and webcam to U2722DE via USB-A
- Headphones to U2755DE via jack
- U2722DE (USBC 90W port) to WD19TBS (USBC Type C port)
- U2715H (DP) to WD19TBS (DP)
- WD19TBS main cable to XPS15 4k USBC
Everything is working (including 130W power supply) except for the U2715H resolution. It is running on 1920x1080 29.97Hz instead of 2560x1440 59.951Hz (see attached picture). What did I do wrong?
jphughan
9 Legend
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14K Posts
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November 20th, 2021 21:00
@T_P The fact that Dell makes a system that requires something doesn't mean that every accessory they make will support the requirements of that system. It also works the other way. For example, Dell makes displays that use Thunderbolt for full functionality, and they also make systems that don't support Thunderbolt, which wouldn't be able to use that display to its maximum potential. (That said, I do find it a bit strange that the first XPS 15 to run 130W over USB-C was introduced in late 2015, and here we are in late 2021, and Dell still hasn't made any USB-C display that provides 130W.)
In terms of your options, they are correct. In terms of the questions:
To check power, go into the BIOS Setup and check either the system summary or battery information section. One of those areas should show the identified wattage of the attached power source.
In the dock scenario, you could use either the USB-C or downstream TB3 port to connect the U2722DE. Or you could use a regular DP cable for video and also connect a USB-C to USB-A cable for USB 3.x data (USB-C side plugged into the USB-C input on the display, USB-A side connected to the WD19TB). That cable should have been included with the U2722DE.
In terms of resolution, first of all I realized I made a mistake earlier. I thought the U2715H was a 1080p display, because these days Dell uses "H" for 1080p and "D" for QHD. But I'd forgotten that back in the days of the U2715H, they used "H" for 16:9 displays in general, including those with QHD. So your bandwidth situation was even worse than I realized in the USB-C scenario! Anyway, the dock's DP outputs only support DP 1.4 if the source system does. But that's not an issue because you don't need DP 1.4 for your display setup. A single full DP 1.2 interface is enough to run 4K 60 Hz, in fact a single interface can run dual QHD on its own. The problem in your USB-C setup is that you only have half of a DP 1.2 interface since you're also running USB 3.x. But when your system is using Thunderbolt, it can run two full DP 1.2 interfaces and USB 3.x all simultaneously. So yes, you'll have enough bandwidth for dual QHD, in fact you'd have enough for triple QHD or dual 4K 60 Hz.
Good luck!
jphughan
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14K Posts
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November 18th, 2021 20:00
@T_P The bad news is that this isn't going to be a good setup.
The reason you're having an issue is that the XPS 15 9500 is a DisplayPort 1.2/HBR2 system, not a DisplayPort 1.4/HBR3 system. HBR2 offers less video bandwidth than HBR3. A full DP 1.2/HBR2 link would be enough to run QHD (2560x1440) and FHD (1920x1080), but the U2722DE is configuring the USB-C link to run both video and USB 3.x data. Running USB 3.x data cuts video bandwidth in half, and half of a DP 1.2/HBR2 link is only enough for a single QHD display at the standard 60 Hz refresh rate. You don't have enough bandwidth to run an FHD 60 Hz display in addition to that. The U2722DE does have a USB-C Prioritization option that can be used to have the display configure the USB-C link for full video bandwidth, but that will drop USB 3.x data speeds down to USB 2.0, which will bottleneck your Ethernet connection and any USB 3.x peripherals you have connected to the display. If you had an HBR3 system, you would be able to run QHD+FHD -- actually even QHD+QHD -- and USB 3.x simultaneously over USB-C, but your system doesn't support that.
The additional possible issue you might want to be aware of here is that the U2722DE only provides up to 90W of power. The XPS 15 9500 can only function optimally on 90W if it has ONLY an Intel GPU. If your system has an NVIDIA GPU, then it would be designed for a 130W power source, and therefore running it from a 90W power source may result in slower battery charging and/or reduced performance, especially when using the NVIDIA GPU.
The only way to get your two displays and USB 3.x data and enough power to run your system properly all over a single cable would be to use a Dell Thunderbolt dock like the WD19TBS. If you don't want to do that, then for power you may want to consider connecting the system's power adapter directly. It's completely fine to have that power source and a USB-C display that supports power delivery connected simultaneously. Your system would choose the higher wattage power source and ignore the other; it won't cause any damage. And then in order to get your displays working properly, you'd have to choose one of these options:
T_P
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November 19th, 2021 10:00
Wow. Thank you for your time jphughan. Your detailed post helped me understand the situation. Though, I'm so disappointed... I indeed have a Nvidia GPU.
First, what is making me upset is that I asked Dell representative if the U2722DE docking station was able to power up my laptop. I wouldn't have bought this more expensive monitor. Two USB-C cable is one thing as XPS15 has 2 ports on the left side. But 3... grrrrr.
Questions:
- Is the DisplayPort version (1.2 vs 1.4) hardware or software related? Graphic card related?
- In the scenario I connect the U2715H directly to the XPS via a USBC to DisplayPort cable, as the U2715H don't have a built in docking station, would the power delivered from the monitor be enough for the XPS (135W)? Or is a USBC splitter could do the job, one for the Displayport cable and one for the power supply?
- Is there a 27" monitor with a usb-c connector that could power up 135W?
Thank you again for your time. I appreciate.
jphughan
9 Legend
•
14K Posts
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November 19th, 2021 14:00
@T_P Happy to help, although I wish I'd had better news for you. To answer your follow-up questions:
The DP version is determined by the capabilities of the hardware involved. In your case, the XPS 15's display outputs are all wired to the Intel GPU, and the Intel GPU built into that generation of CPU only supports HBR2. (The NVIDIA GPU is not wired to any outputs and instead operates only when needed and only as a rendering platform, which then passes completed video frames through the Intel GPU for output. This technology is called NVIDIA Optimus, and it's implemented for battery life reasons, because it allows the NVIDIA GPU to shut down when its performance isn't needed.)
Connecting the U2715H directly to your display won't change anything about the power you receive from the U2722DE. You're not "losing" power from the U2722DE by having the U2715H attached to it. The U2722DE simply only supports 90W output to an attached system. That might be based on the sizing of its built-in power supply.
There are splitters that give you a DisplayPort output and a USB-C power input, but I'm not sure they would work. The reason is that the formal USB PD spec maxes out at 100W. Dell did something proprietary to stretch that out to 130W (not 135W), and they implemented support for running 130W over USB-C/TB3 on some of their docks and systems, including your XPS 15 9500, but you won't find that support implemented on third party products. The USB PD spec was very recently revised to support up to 240W, but the only product on the market that actually supports that is Apple's 140W USB-C charger, and then only when used with their proprietary MagSafe cable. There aren't any USB-C cables that support that new spec yet, and your system was created before that standard existed anyway. But if you want to try a splitter just to see if maybe you can get your power adapter's full 130W through it even if that isn't technically supported, here is the right type of adapter from a manufacturer that I have had consistently good luck with. I guess worst case you could return it, but if it works, then it's a simple and inexpensive way to run both displays, with USB 3.x connectivity to the U2722DE, and optimal power for your system all through two cable connections, thereby keeping one port on your system free.
In terms of displays that support 130W output, again since that's a proprietary Dell implementation, it would have to be a Dell display, and I haven't seen any Dell displays support that level of power output, not even their very expensive displays.
T_P
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November 20th, 2021 17:00
Crystal clear! Thank you again for your explanation.
As the "130W" is a Dell design, it's difficult to understand the reason why the U2722DE can't provide 130W?!
Anyway, for a summary, my options are:
1- Connect 3 cables (1 for U2722DE, 1 for U2715H and 1 for power)
2- Connect 2 cables (1 for U2722DE, 1 for U2715H and power with a splitter usb-c/DisplayPort) but to be confirmed if that deliver enough power
3- Connect 1 cable but buy a WD19TBS dock. Plug both monitors, ethernet and usb3 peripherals in it.
New questions:
- in the scenario 2, how do I know if there's enough power going into the XPS?
- in the scenario 3, I will have to plug the U2722DE in the USB-C Multifunction DisplayPort? I guess yes if I want to use USB3 peripherals with it?
- also in the scenario 3, I will have to plug the U2715H in the DisplayPort 1.4? With that setup, both monitors will be QHD even if my XPS has a displayport 1.2?
Thank you so much again for your time!
T_P
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8 Posts
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December 9th, 2021 07:00
For the sake of posterity, I wanted to note that solution 2 does not work. The cable Matters (usb-c/DisplayPort splitter) mentionned does not provide 130W, only the specified 100W.
jphughan
9 Legend
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14K Posts
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December 9th, 2021 08:00
@T_P Thanks for reporting back. Bummer that you couldn't get 130W through the adapter, although I figured that would be a long shot. Dell's 130W implementation is proprietary. I thought it just might manage to get through that device, but apparently not. Good to know though!
T_P
1 Rookie
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February 19th, 2022 07:00
Hello jphughan,
I finally received my WD19TBS. Here's the way I connected everything:
- Keyboard, mouse and webcam to U2722DE via USB-A
- Headphones to U2755DE via jack
- U2722DE (USBC 90W port) to WD19TBS (USBC Type C port)
- U2715H (DP) to WD19TBS (DP)
- WD19TBS main cable to XPS15 4k USBC
Everything is working (including 130W power supply) except for the U2715H resolution. It is running on 1920x1080 29.97Hz instead of 2560x1440 59.951Hz (see attached picture). What did I do wrong?
Thank you for your support.