U3818DW, setting up PBP with two laptops

Question

Hi,

I can't get this monitor to display correctly inputs from two laptops (using the full screen in native resolution) and I don't know if the problem is just settings/cable connections or that the laptops can't support the native resolution. The laptops are:

HP EliteBook 835 G7 (8RN40AV), with AMD Radeon RX Vega 7 integrated graphics, 512 VRAM and these ports: 2 USB-C (1 is Alt Mode, 3.1 Gen 2, 2 are Thunderbolt 3 compatible), HDMI 2.0., 1 USB 3.0

Lenovo Yoga X1 (20JD-CTO1WW), with Intel HD 620 integrated graphics, 128 VRAM and these ports: 2 USB-C (1 is Alt Mode, 3.1 Gen 2, 2 are Thunderbolt 3 compatible), HDMI (not sure which version), 2 USB 3.0

What's the best way to connect this laptops in PBP mode?

Thanks!

jphughan · Accepted Answer

@bob2727 Both of those laptops have GPUs that will support displays at least up to 4K 60 Hz, in fact even older Intel GPUs could do that. You just need to connect to the display in a way that can carry the required amount of bandwidth. HDMI 2.0 would be able to do that. HDMI 1.4 would not. That's partly why I recommended USB-C to DP. The oldest DP standard that was supported over USB-C was 1.2, which is enough for 4K 60 Hz and therefore more than enough for that display's 3840x1600 resolution, even if you wanted to run the entire display area from a single system. Although that just reminded me that for the system connecting via USB-C, you might find that you can only run USB 2.0 data speeds over that link in order to keep enough video bandwidth available for the display. If you need USB 3.x data speeds for whatever you plan to connect to the USB ports built into the display, you'd need to run a separate USB 3.0 cable to the system for that. Fortunately, the display has two USB-B "upstream USB" ports, so you'd be covered there.

In terms carving up the display though, I'm afraid I've got some bad news there. The display's PBP mode will only cut the display area in half. This is shown on Pages 41-42 of the display's User Guide here. It will not shift the "dividing line" based on the resolutions you choose on each source system. In terms of the resolutions you will be able to send to the display, I'm not sure exactly how that works. A 3840x1600 display split vertically results in two 1920x1600 "tiles". But I'm not sure if the display will actually accept a 1920x1600 signal. It might only accept 1920x1080 and then show black bars along the top and bottom edges of each signal. There's a note on Page 41 of that guide saying "The images under PBP will be displayed at the center of the screen, not full screen." I'd suggest doing some research online to see if you can find posts from actual owners as to what your options will be when you've got PBP running. But you definitely will not be able to run your 2/3 + 1/3 split -- although I think these days having a display area only 1280 pixels wide would feel pretty cramped anyway.

The ultimate PBP display is probably a "super-ultrawide" 32:9 display like Dell's U4919DW, which runs 5120x1440. In that case, cutting it in half still leaves you with a pair of normal 16:9 widescreen tiles, specifically with resolutions of 2560x1440, i.e. the standard resolution of a 27" display. And indeed the U4919DW is essentially two 27" display panels placed side-by-side and fused together to operate as a single panel when desired, or as two PBP tiles if preferred.

jphughan · Accepted Answer

@bob2727 DisplayFusion appears to allow you to carve a single display run by a single PC into multiple displays. I didn't look into it deeply, but it didn't appear to allow you to define a tile that would be generated by a completely separate PC. And even if that were available, that would essentially involve one PC receiving a remote desktop feed from another, which in turn would mean that from the display's perspective, only one PC would be using the entire display area, AND it would also likely require DisplayFusion to be installed on both PCs involved in this setup.

I run dual 27" displays myself and really like the solution. I prefer it over ultra-wide displays because in my case, I'm almost always multi-tasking, and having physically separate displays helps me mentally compartmentalize my various tasks. Ultra-wide displays are great if you have a single application that can make good use of the entire canvas, such as a video editing application or of course a game, but those aren't my use cases.

But anyhow, good luck with your experimentation!

jphughan · Answer

@bob2727  Both of those laptops have USB-C ports that support video output and seem to support system charging (I know the X1 Yoga does, not sure about the HP).  And if the HP does, then both laptops are designed for power levels that the U3818DW supports providing.  But since you've only got one USB-C input, you'll have to decide which system you want to charge from the display at any given time.  For the other system, the best way to get PBP functionality is to use a USB-C to DisplayPort cable for video, and then if you want to use USB peripherals connected to the display with that laptop, run a USB 3.0 cable from one of the USB-B 'upstream USB' ports on the display down to a USB port on the same laptop.  Then in the display, associate the DisplayPort input with the upstream USB port you used, so that if you're ever using the full display for that system, i.e. NOT using PBP mode, the display will know to activate that upstream USB port when you're using the DisplayPort video input.

bob2727 · Answer

Very useful - thanks! This takes care of the best way to connect the two laptops to the monitor. I still don't know if my laptops can support the display with their graphics chipset/memory though. Do you have any view on this? No sense in working on the setup if these can't "power" the monitor (pixel-wise).

So far, I connected both via HDMI (my monitor came w/o the USC-C cable!) and I couldn't get to display 3840 x 1600. Also, my ideal setup would be 2/3s of the display for one laptop and 1/3 for another. Does that mean that I need to set the resolution of one laptop to 2560 x 1600 and 1280 x 1600 for the other?

Thanks!

bob2727 · Answer

Super useful - thank you very much! I did some research and people have been able to do what i want via a Displayfusion software. The thing is I'm VERY restricted in what software I can install in my work laptop - essentially, nothing that's not issued by the company. I think I'll just connect one laptop to the monitor via USB-C. This should simplify things. Alternatively, I might return the monitor and switch to two 27" ones (2560 x 1440). I have two coming in for my wife so I'll be able to compare.

Thanks again!

bob2727 · Answer

Uff. Thank you for the follow up. The main objective in getting an ultra-wide is multi-tasking. I did like the idea of not having a bezel in the middle but your thought of using it to compartmentalize is exactly the reason why my wife is going with that setup. I think I'll do that too.

DelltaForced · Answer

Hi,

I just spent almost two hours with Dell Tech Support on Picture-By-Picture (PBP) scaling issues with this monitor and firmware M3B106. I found a fix and submitted a request for a firmware update.

My symptoms: when in PBP mode, the monitor would display each input with a "Widescreen 21:9" aspect ratio. Widescreen format creates a letterbox or picture box. Instead, PBP should display each input's aspect ratio in "1:1" format by default. The monitor's aspect ratio settings are unavailable to the user when in PIP/PBP mode (monitor's menu option of Display->Aspect Ratio is grayed out).

The fix: in Windows 10, change the screen refresh rate to "60 Hertz" in Display Settings->Advanced Display Settings->Display adapter properties for Display 1->Monitor. Scaling issues disappeared for me. My screen refresh rates were previously set to 30 Hertz, or there was a difference in refresh, e.g. one at 60Hz and the other at 30Hz.

Good luck!

DelltaForced · Answer

The U3818dw monitor accepts two 1920x1600 inputs when in PIP/PBP mode.

What is displayed on each side of the screen will depend on the resolution that the computer is outputting. If you transmit 1920x1080, then you'll get letterboxing; if you transmit 1920x1600, the whole screen will fill up.

I've used this monitor with 8-year old graphics cards and they all work in 1600p mode-- the monitor tells the graphics card what resolutions it accepts. If you have a docking station in the middle, then it may limit the resolutions presented to the computer.

The monitor has some firmware issues, so displayed images may change based on the refresh rate the computers' display adapters are set to in Windows. Use 60Hz!

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U3818DW, setting up PBP with two laptops

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