How to drive four displays from DELL Precision 5540

I have the same issue too.

Have you figured out how to do this. I just purchased the same Precision 5540 and I'm now facing the same problem.

Thank you

I also want to use 3 external monitors + the laptop screen.

My setup is:

Precision 5540 w/ i7-9850H, Quadro T1000, 32G RAM 

Dell WD19TB thunderbolt dock

2x 1920x1200 screens

1080p TV, which I use at times, without needing to switch off one of my screens.

My 6 years old 15'' MacBook Pro Retina does it with ease, and this super-duper Dell can't. It's simply not logical ..  

@knaumov  On the Precision 5540, the Intel GPU controls the built-in display and all of the display outputs.  Intel GPUs support a maximum of 3 displays.  On the 15" MBP, the discrete GPU controls the display output connectors, and it supports 4 displays all on its own, while the Intel GPU controls the built-in display.  There are pros and cons to each of these designs, but the former design does limit maximum display quantity to what the Intel GPU can handle.  (I wrote an explainer post on the various implementation options of dual GPU systems and their benefits and tradeoffs here if you're curious.)

So if you want four total displays, you have two options here:

• Run at least one of the external displays through a USB dongle that relies on "indirect display" dongle like DisplayLink.  These displays are not driven directly by any GPU and therefore don't count toward its maximum display count.  But DisplayLink has some potentially significant drawbacks that I've written about in the post marked as the answer in this thread.
• Get a laptop that has a "hybrid" GPU wiring design like your 15" MBP or where the NVIDIA GPU controls even the built-in display.  Within Dell's product line, the only systems I know of that offer this are the Precision 7000 Series (separate BIOS options allow you to choose which GPU controls the built-in panel and which controls the display outputs), and also the XPS 17 9700 when optioned with an NVIDIA RTX GPU (one BIOS option allows you to switch between all-Intel and all-NVIDIA, including the built-in display).  The XPS 17's sister system the Precision 5750 may work the same way, but I'm not 100% sure.  Or if you're willing to look outside of Dell, the ThinkPad X1 Extreme and its sister system the P1 are direct competitors to the XPS 15 and Precision 5500 Series, respectively, and those systems have the display outputs wired to the NVIDIA GPU with a BIOS option to control which GPU runs the built-in display.  I have an X1 Extreme Gen 2 and when the Intel GPU controls the built-in display, I can get 4 external displays all running simultaneously alongside it.

Thank you very much for the details. 

I'm not going to change the laptop. Strange the Dell architecture team took such decisions for Precision 5540 and leaving only the even higher end models capable of running 3 external screens + that laptop panel. 

Having my TV connected full time is not that essential. It certainly is a convenient to have it enabled as a 4th screen, but I'll do fine even if I need to switch it on/off with some of the other screens. I hope Intel's limitation can be reconsidered at some point and they can enable it through driver or firmware update. Even if not, so be it.

I own an HP dock G2 which is on the list of the Display Link devices. I may give a shot with it, instead of the WD 19TB. The bad is that my modification is not recognized as a legit charger, but I will see how to work around it.

Thank you!

@knaumov  If it helps at all, you don't have to physically disconnect the third external display/TV.  You can just set it to "Disconnect this display" in Windows Display Settings whenever you want to light up the built-in display, or vice versa when you want to light up that third external display.  Otherwise, if the limitations of DisplayLink aren't an issue, then a DisplayLink-based dock may indeed be the way to go, although as you say you'll then have a power issue to deal with.  That's because the Precision 5540 is designed for a 130W power source, which is above the 100W max of the USB PD spec.  Dell did something proprietary on some of their systems and docks to stretch the spec to run 130W over USB-C/TB3, but you won't find that implemented elsewhere.  So at that point you either need to keep power connected separately or run the system from an undersized power source, in which case you may see reduced battery charging speeds and/or throttled performance, especially when running workloads that involve both the CPU and GPU.

As for the system design, I agree it's disappointing for power users.  But you can't please everybody.  I remember a discussion with someone here who posted a thread complaining that his Inspiron Gaming system had its display outputs wired to the NVIDIA GPU.  He wanted them wired to the Intel GPU to improve battery life, since the system's design meant the NVIDIA GPU had to stay active whenever an external display was connected, even if nothing graphics-intensive was going on.  I pointed out the gaming-related benefits of giving the NVIDIA GPU direct control of the outputs and suggested that it arguably made sense for Dell to prioritize gaming functionality over battery life on an "Inspiron Gaming" system, but he was adamant that Dell had made a bad design decision there.  But for systems where Dell has the Intel GPU controlling all outputs, I've seen people complain that they can't run more displays, or VR, or G-Sync, etc.  And if Dell implemented the necessary hardware design to allow a BIOS option to be used to choose which GPU controlled the output, customers might complain that the systems were too expensive.  But the tide may finally be turning here.  The new XPS 17 is the first system other than the Precision 7000 systems where I've seen a BIOS option to change GPU control.  It's only available on configurations with an RTX GPU, and unlike the Precision 7000 systems you can't change control of the built-in display and the display outputs separately, but it's at least something.  So the XPS 15 may follow suit.

I really wouldn't hold out for a driver or firmware fix for this though.  Older Intel GPUs only supported two simultaneous displays, and they never got an upgrade to three displays.  You needed a newer Intel GPU for that.

I have a DELL Precision 5550. Facing identical issues. My IT dept just issued it to me. I am using the WD19TB dock. This is suppose to be a thunderbolt 3 dock. Long story short, I have two external monitors connected to the dock's the display port. The third external monitor, connected through HDMI (from the dock as well) - No Go !!. I don't see all three monitors working successfully.

I've updated all the firmware starting from BIOS to video drivers to dock - all useless. Its a company issue laptop so I guess I'll use it but to be honest, if I spent my money on it, I would seriously be considering returning this.

I keep reading various posts stating three external monitors can be done. I'm only using 1920 X 1080 monitors, no 4K. Best I get it two monitors output through display port. The third 1920 X 1080 monitor, connected through HDMI is flakey, and it only works..sort of...when close the lid on the laptop. When I do see the display on it, the resolution is way off.

Apologies for this rant. I'm THAT frustrated with this situation.

@xmfan  Not being able to run 3 displays reliably isn't identical to the issues being discussed here of not being able to run 3 external displays plus the built-in display simultaneously.  The latter is expected.  Your issue is not.  The WD19TB when paired with that system should indeed be able to run triple 1080p when they're connected via DP1, DP2, and HDMI -- as long as the built-in display is disabled, which requires running Windows rather than Linux, which doesn't allow that.  Closing the lid certainly achieves that, but you could also keep the lid open and manually set it to "Disconnect this display" in Windows Display Settings.

If you've already updated all drivers and firmware, the only thing I can suggest as a possible workaround would be to get a USB-C to DisplayPort cable/dongle to connect one of the displays currently using a DP output over to the "downstream TB3" port at the very edge of the dock instead.  This will not only use a different dock output, but will also move that display over to a different GPU interface.  When the WD19TB is paired with a DP 1.2/HBR2 system like the Precision 5550, one GPU interface is allocated to the downstream TB3 port and the other is shared across all other ports.  So maybe distributing the displays will help here.  (Note: Do not confuse the downstream TB3 port with the regular USB-C port near the HDMI output.  The regular USB-C port and the HDMI output cannot be used simultaneously.)

Of course that workaround shouldn't be necessary since your current setup should work as-is, but unfortunately it's also true that not everything that should work in the tech world always does.  I'm working with two people right now for example who just found that their XPS 15 9500 (the sister system of the Precision 5550) hangs at boot if the system is started while connected to a 5120x1440 display and the lid is closed.  This has been confirmed with multiple 5120x1440 display models, connected with and without a dock involved.

Hopefully your IT department will spring for a USB-C to DisplayPort cable/adapter to allow you to test this.  They're inexpensive and pretty easy to get.