XPS 15 7590 + Triple 4k?

@edgarlemos  one more thing I forgot to mention above.  If all of your displays are actually TVs, I'm guessing you don't have DisplayPort inputs as an option and will instead have to use HDMI 2.0.  In that case, be aware of two things:

- Garden variety DisplayPort to HDMI cables may not work unless you find a cable that's specifically rated for HDMI 2.0, or a DisplayPort to HDMI 2.0 dongle plus an HDMI cable that has the High Speed or 18 Gbps designation.

- When you're running dual 4K displays from the WD19TB, one of them has to be connected to the dock's "upstream" Thunderbolt 3 port.  It doesn't have to use native Thunderbolt, i.e. a regular USB-C cable is fine, but it has to be on that port of the dock.  The other display can be connected to any other display output.  Note that the upstream Thunderbolt port is the one on the far side of the dock, NOT the USB-C port near the HDMI output.

Based on those two constraints, I would recommend connecting one of the TVs to the HDMI 2.0 port built into the dock and then getting a USB-C to HDMI 2.0 cable to connect the second TV to the "upstream" Thunderbolt port.

Thanks @jphughan !!

In fact that seems fine!
I Could Connect 1 Tv to the Laptop's HDMI, 1 Tv to the Docks HDMI and another to the TB port.

But if you say that there have been issues with connecting this, I stay skeptical..

Are there other Dell Laptops that would be more suitable for a 3x4k Setup like this and that have great battery life as well?

Best Regards

@edgarlemos  I haven't researched Dell's product line extensively, but if you want to run triple 4K you'd need both Thunderbolt 3 and an HDMI 2.0 output or a separate DisplayPort/USB-C output.  That already narrows down the options considerably, and then adding a long battery life requirement would rule out systems like the Alienware and Precision 7000 Series systems.  Come to think of it though, the XPS 13 7390 models (both the standard style and 2-in-1 version) might be able to do this.  Both of them have dual Thunderbolt 3 ports, and the standard version also has another USB-C port that's capable of video output on top of its dual TB3 ports.  So with either of those systems, you could connect a Thunderbolt 3 dock for dual 4K displays and then a USB-C to HDMI 2.0 cable for the third.  The XPS 13 models would also give you much better battery life than the XPS 15, especially the 2-in-1 version since that uses Intel's new Core 10th Gen "Ice Lake" CPUs, which are a significant performance and battery life improvement over previous generations.  By comparison, the standard XPS 13 7390 also uses Core 10th Gen CPUs, but models that are just a minor refresh of an architecture that was introduced with Core 5th Gen.  Yes, Intel is using Core 10th Gen to describe two radically different architectures.  Intel unfortunately has made their processor naming even more confusing with Core 10th Gen than it was already, which is really saying something.

The major things you'd lose going with either XPS 13 compared the XPS 15 are:

- The 15" display
- The NVIDIA GPU
- The higher performance 45W H Series processors (both XPS 13 models use 15W CPUs, and though the 2-in-1's CPUs are better, they wouldn't outperform the XPS 15)
- The built-in HDMI port (although I think the additional TB3 port and possibly USB-C port makes for a better setup anyway)

The downside here is that I haven't personally confirmed or seen a report as to whether either XPS 13 model will actually run a triple 4K setup when all of them are external.  That's obviously a pretty rare setup, so data might be hard to find.  The GPU specs indicate that it's possible, although again you'd have to have the built-in display disabled.  The only hesitation in my mind is the question of whether the motherboard has enough GPU outputs wired to its ports to run all of that as external displays.  It's possible that if you're already using the Thunderbolt 3 port for dual 4K, then there isn't another GPU interface still available to drive a display connected to one of the other USB-C/TB3 ports.  I just don't know.  But if triple external 4K display support and long battery life are important to you and you don't necessarily need the things you'd be giving up from the XPS 15, then if I were in your position, I would probably just get the XPS 13 7390 2-in-1 with a WD19TB dock and test it out.  Worst case, you return it.  Best case, you get a system that's very compact and has huge battery life and can drive the setup you want.

@edgarlemos  here's one other option that would sort of sidestep questions around GPU limits entirely.  This adapter plugs into a regular USB port and gives you dual HDMI 2.0 outputs to run two displays each at up to 4K 60 Hz.  It uses a "indirect display" technology called DisplayLink, and since displays attached this way do not tap directly into GPU outputs (which isn't even possible on a regular USB port), you don't have to worry about things like the maximum display configuration a given GPU supports, how many outputs are wired on the motherboard, or whether they're working properly.  You could just plug this into a USB 3.0 port on the dock, and you're good to go.  I realize you only need one additional 4K display beyond what the dock would already handle, and there are some versions of these DisplayLink adapters that only have a single HDMI output, but the ones I found were limited to 4K 30 Hz.  I can't find a single output 4K 60 Hz version, only dual 4K 60 Hz for some reason.

So why didn't I mention this option earlier?  I normally don't recommend using DisplayLink because the way it works can introduce some potentially significant drawbacks for certain use cases.  I wrote about those in detail in this thread, specifically the post marked as the answer.  However, if you only need these displays for trading/general productivity work as opposed to gaming or full screen video, then you're actually the perfect use case for this type of technology, which is explicitly meant to allow PCs to run more complex display setups than their GPU and/or built-in display outputs would normally allow.  In fact, technically you could buy two of these adapters and plug them both into any system that had two USB 3.0 ports (or even through a USB 3.0 hub) and any PC would then be able to run four 4K displays through those two adapters.  Also note that even if you do plan to do some gaming or full screen video, just avoid doing it on the display you attach through this DisplayLink adapter, and instead do it on one of the two 4K displays you've got plugged into the dock's actual video outputs, since those displays would be driven directly by the GPU.

So if you don't think you'd be affected by the DisplayLink drawbacks I discussed in the thread I linked above, then I would say you should just buy either the XPS 13 or XPS 15 system you want plus a WD19TB dock.  If you can make triple 4K external displays work using one of the setups I suggested earlier, then fantastic.  If not, then buy this DisplayLink adapter, plug it into the WD19TB, and connect the third display that way instead, and you should be good to go.

Thanks for all the information @jphughan !!

In fact I've searched for DisplayLink solutions before but those constrains gets me skeptical.

In fact CPU Performance is needed for some Software that have to process indicators and multiple data analysis. So how much of CPU usage would it kill running a Setup with one adapter like those? Regarding Video/gaming in that screen (Display Link) that just won't work or will it be more CPU demanding?

In that explanation Post you say one could get some jittery image. Many of the software are showing constant price updates on stocks and charts. Although it won't be pixel by pixel change like in a movie/game, they will change a lot.

The reason I prefer the XPS 15 is precisely because of the i7-9750H processor which is better than the XPS13's and I can update the RAM and SSD.

Connecting the USB Display Link to the Dock wouldn't be bandwidth exhausting? It'd be perfect (only one cable) but maybe connecting to the laptop's USB would be better, right?

Regards

@edgarlemos  the CPU utilization and level of blocky compression artifacts and judder is proportional to the amount of change occurring on the display, since the more motion there is, the more work DisplayLink and your CPU have to do.  The reason I don't think you'll have an issue is because even if you have a lot of figures on your dashboards updating on a routine basis, those figures as a percentage of the total pixels on the display will still be quite small, and even if they updated twice per second (i.e. 2 frames per second), that would still be 30x slower than a typical full screen video (60 frames per second) that can be a problem on DisplayLink.  As a result, and especially considering you'd be getting a current generation CPU, your CPU utilization will be minimal, and I don't believe you'll see any display issues.  If DisplayLink couldn't work even for dashboards, then it wouldn't really be usable for anyone, but it is.  Just not so much for video and gaming.

As for what would happen if you tried to watch video or play games on a DisplayLink display?  Full screen video might be ok on a modern CPU.  Gaming won't work so well, especially because of the issue I called out in that other thread mentioning that a DisplayLink display can only be accelerated by the primary GPU in the system, which would be the Intel GPU -- so the NVIDIA GPU would be unusable for content on the DisplayLink display.

As for connecting it to the dock, you won't have a bandwidth issue.  Thunderbolt 3 is 40 Gbps.  Dual 4K displays driven by the GPU require about 32 Gbps.  So even if your DisplayLink display adapter completely saturated a USB 3.1 Gen 1 link (it doesn't even come close), that would be 5 Gbps, which you'll have available.  And again, since the content on your display as a total percentage of pixels is still going to be fairly static AND not updating anywhere close to the rate of a full screen video, that DisplayLink display actually won't consume very much bandwidth at all.

In terms of Ice Lake, part of that architecture involves a move from 14nm down to 10nm fabrication.  Right now even Ice Lake is in short supply, in that only some Core 10th Gen CPUs have gotten it and there are relatively few systems currently on the market that even use those chips.  So it looks like Intel might be having yield issues.  But the only CPUs that have Ice Lake versions right now are the low power 15W CPUs meant for systems that would otherwise have used "U Series" CPUs.  The XPS 15 uses the higher performance 45W "H Series CPUs", and last time I looked at Intel's leaked product roadmaps, those CPUs aren't slated to get a move to 10nm until I think 2021 -- and that assumes everything goes to plan.  I had planned to wait for Ice Lake before getting my next laptop, partly for battery life but mostly to get the newer GPU that supported DisplayPort 1.4 over USB-C -- but when I read that, I decided I couldn't wait that long.  So instead I got a laptop that uses the NVIDIA GPU to control the display outputs, which means the Intel GPU limitation doesn't really matter.

For USB 3.1 Gen 1 vs. Gen 2, the USB-C port on the XPS 15 7590 supports 3.1 Gen 2.  As for its USB-A "regular USB" ports, those are indeed 3.1 Gen 1, but that's pretty common.  USB-A ports that support 3.1 Gen 2 do exist, but they're not very widely implemented on systems, and consequently there are very few products that use a USB-A port and support 3.1 Gen 2.  Another reason is that realistically, there are very few USB products that even use even all of the 5 Gbps bandwidth available on 3.1 Gen 1, never mind 10 Gbps.  A SATA 6 Gbps SSD might get a bit of extra performance from using 3.1 Gen 2, or I guess a 10 Gb Ethernet adapter, but that's about it.  An NVMe SSD would still be significantly bottlenecked even over 3.1 Gen 2.  You'd need Thunderbolt to really capitalize on that, but NVMe SSDs in Thunderbolt enclosures like the Samsung X5 (not the T5) are expensive.