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XPS 7390, Thunderbolt, eGPU/Docks and OS Compatibilities
Hello,
I have a few questions regarding the upcoming XPS 7390 2-in-1 with its Thunderbolt 3 technology, general OS compatibility, and eGPUs/Docking Stations. All answers will be appreciated I am trying to get everything figured out before college fall semester. I will also be using linux (Fedora).
Q1: Will the 7390 have 8 total PCIe lanes (4 each port) available to Thunderbolt, or only 4 (2 each port)?
The spec sheet says this:
1. Thunderbolt™ 3 with power delivery and DisplayPort (4 lanes of PCI Express Gen 3) | ... | 3. Thunderbolt™ 3 with power delivery and DisplayPort (4 lanes of PCI Express Gen 3)
I interpret this as the laptop will have 8 total lanes, and both ports will have 4 available lanes. I've looked at other Dell laptop specs and they all seem to be formatted this way. If it means there's only 4 total, the eGPU I intend to use it with will suffer.
Q2: If I hook up an eGPU and the WD19TB dock simultaneously, will it break the internal charging die?
I want to run 3 4k monitors at my desk, but obviously the iGPU can't handle such a resolution. Running a desktop graphics card in an enclosure will work, but it runs over one of the Thunderbolts. I also need Ethernet, an SSD, 3.5mm jack, and all of my USB peripherals to run on the other Thunderbolt to avoid any throttling.
So my question is, if I have an eGPU hooked up on one of the TB ports, and the WD19TB hub on the other, (since both charge the laptop separately) will the laptop choose one source to draw power from? Or will it overload the laptop and break it? And if it will break the laptop, what is a safe solution so I don't have to run everything over a single TB cable and encounter bandwidth issues?
Q3: Do Dell features in laptops work on Fedora?
The upcoming XPS will have features like a fingerprint reader, display digitizer, pen support, etc. Are these things supported well in the linux kernel? Or will they be Windows only features? I'm assuming they won't change drastically between each refresh of the laptop, so answers based on previous models is good.
Thanks again everybody!
jphughan
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July 20th, 2019 11:00
As for 4K, I’m not sure why you consider it obvious that the iGPU couldn’t handle that. Intel GPUs have been able to handle that resolution for several years, in fact the XPS 13 has had a 4K display as an option for a few generations now, and it has been able to run triple 4K displays for a while too, at least when that setup is a 4K internal display and dual 4K external displays. If you want all 4K displays to be external, I’m not sure the iGPU has enough DisplayPort lanes wired to its external display ports to support that, but if it’s going to work, you’d want to connect two displays to the WD19TB dock (which definitely works) and connect the last display directly to the system using a USB-C to DisplayPort cable. Also note that with the WD19TB dock, if you want to run dual 4K displays from it, one of them has to be connected to the “upstream” Thunderbolt port on the end of the dock using a USB-C to DisplayPort cable. Check the WD19TB manual for details. Finally, the Intel GPU only supports three simultaneous independent displays total, regardless of how they’re connected, so triple external displays means you’d have to disable the built-in display. But I think I remember reading something about Linux not being able to completely disable the built-in display, and if that’s true, you’d only be able to run dual external displays anyway.
You can have multiple power sources attached simultaneously without breaking anything. The system will only use one, though.
Knighte
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July 20th, 2019 12:00
Thanks for the speedy response! Very informative. The multiple power sources was my main concern.
Sorry I was a little unclear about the eGPU though. I'll be getting triple 4k monitors (12k total) in a surround setup. I have a GTX 1080 right now, which has x3 Displayports, and will just run it in an enclosure. I just meant that the iGPU can't handle 12k (13k if I can't power off internal display) output.
jphughan
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July 20th, 2019 14:00
@Knighte the iGPU can indeed handle 12K output. As I said, the XPS 13 for a few generations now has offered a 4K internal display and has been able to run dual 4K external displays simultaneously. The part I'm not sure about as I said is whether it can do triple 4K when all displays are external. But if you're talking about not being able to handle 12K in a gaming context with reasonable performance, then yes that's definitely true. Hopefully others are able to answer the rest of your questions, especially the ones related to Linux where I know very little!
RubyeJ
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July 20th, 2019 20:00
See KB article, "Thunderbolt 3 40gbps Data Transfer Rate" (https://www.dell.com/support/article/us/en/04/qna44089/thunderbolt-3-40gbps-data-transfer-rate?lang=en) for the number of PCIe lanes.
Cheers,
RubyeJ
jphughan
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July 20th, 2019 22:00
RubyeJ
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July 21st, 2019 05:00
Knighte
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July 21st, 2019 06:00
Thank you @RubyeJ for the list! It is helpful to see that other laptops have the same notation and it seems that the 7390 has 4 lanes on each port. Even though the laptops are outdated and have only one TB port, I can't imagine Dell would put total PCIe lanes available in the ()'s rather than what's available through that one port. I may call a Dell rep just to confirm this, but I think it's safe to assume for now that there's 4 on each end.
And what @jphughan said that it won't charge at the same time and break it, I'll be able to run the dock and eGPU simultaneously with 4 lanes each! This is great. Now I just need to know if the hardware doesn't play nice with linux, and then I'm all set to buy!
Thanks again guys
jphughan
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July 21st, 2019 08:00
jphughan
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July 21st, 2019 08:00