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I have a PC with an AMD Kaveri APU running Linux. I'm just fine with the internal GPU but would like to connect to a displayport display and my motherboard does not have a connector. Is there any (cheap) way that I can add a displayport connector through PCIe or something? I have not managed to find a direct PCIe to displayport card but am exploring options like PCIe to USB-C to DisplayPort but I'm not sure if that would even works and it seems rather expensive.

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  • You have not given us enough information about the hardware to answer your question.
    – Ramhound
    Feb 27, 2016 at 16:48
  • What information do you require regarding the hardware ?
    – Gerharddc
    Feb 27, 2016 at 17:02
  • I have not managed to find a direct PCIe to displayport card That is weird since they are very hard to miss. Just go to a website which compares cards and select graphical cards which include DP. Over here these start at about EUR 60
    – Hennes
    Feb 27, 2016 at 17:06
  • @Hennes ok yes I can easily find a full graphics card but I don't want an extra GPU. That's why I said I was happy with my integrated one. Sorry for not being clear.
    – Gerharddc
    Feb 27, 2016 at 17:12
  • In that case there is no solution. PCIe to USB-C to DP also does not exists. What does exist is Thunderbolt3 (from PCI and DP connectors on the motherboard) to thunderbolt with an USB-C connector. But unless you already can tap the DP out from the motherboard that is not going to help.
    – Hennes
    Feb 27, 2016 at 17:15

3 Answers 3

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Getting more ports without an extra GPU is impossible. The CPU graphics outputs are simply not accessible to PCIe (or other) extension cards.

If your performance requirements are low, you could also go for a USB graphics adapter.

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  • Why can external displays run over USB but not PCIe? And would USB ports from a PCIe adapter be able to run an external display?
    – Gerharddc
    Feb 27, 2016 at 17:40
  • There is no difference between USB and PCIe though? The USB adapter would also contain a GPU. It’s simply another format containing the same thing.
    – Daniel B
    Feb 27, 2016 at 17:41
  • Ok but those USB adapters (for HDMI at least) are far cheaper than a proper GPU and probably do not include a full GPU?
    – Gerharddc
    Feb 27, 2016 at 17:46
  • They indeed for not include a full GPU. The calculation are typically done on the main computer, results are compressed and then transfered to an output device. Marketing just calls is 'external graphics card' but the only true part of that is 'external'.
    – Hennes
    Feb 27, 2016 at 17:52
  • They do. It’s just very low performance and doesn’t contain features like 3D acceleration. Of course, it’s arguable what actually is a “full GPU”.
    – Daniel B
    Feb 27, 2016 at 17:53
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Getting more connectors which carry a video signal is not always trivial. You need a source for that signal.

The onboard GPU is usually hardwired. You can not simply add more connectors. What you can do is:

  • Buy an additional graphics card with the desired output.
  • Buy some software which emulates a graphics card and which ships with some connector to output it (usually emulated on the CPU and then transfered over the USB protocol to a special device). Must shops simply call these 'USB graphics cards' even though they do not do the graphics themselves.
  • Have one of the few motherboards which are specially prepared for special TB3 add in cards. Match the right motherboard with the right card and use the right cables. IIf you had one of these I assume you would know.
  • Have a motherboard with already integrated Thunderbolt3. Which are currently coming on the market.

These last use the Aline Ridge chip, which takes an already prepared DP signal from your onboard GPU and optionally muxes it to some cables on the thunderbolt port. Note that this port may look like USB-c, but it is different.

This is basic PCI-e to USB:

Basic PCI-E to USB controller

And this is thunderbolt3:

USB with Thunderbolt controller

Adding a random USB card which just happens to have the same physical plug as TB3 will not yield a connector which supplies video information.

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  • There are no TB AIC receiving the DP signal internally that I’m aware of. They all have external DP inputs.
    – Daniel B
    Feb 27, 2016 at 17:56
  • @Hennes I guess that makes sense, but how on earth does DisplayPort over actual USB-C (not thunderbolt) as outlined in displayport.org/what-is-displayport-over-usb-c work?
    – Gerharddc
    Feb 27, 2016 at 17:57
  • Easy: the USB C controller have DisplayPort signals routed to it, that's why the Sunix upd2018 / delock 89582 / Dell 1H0Y3 / Dell M0W58 / Dell WYY76 (same card, many labels) have a DisplayPort input. Same thing if it's not a separate card.
    – chx
    Apr 10, 2020 at 18:10
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The way AMD labels their CPU pins is a bit harder to understand than Intel -- but they are not fundamentally different in this regard. So, if you were to look at the LGA 1150 datasheet table 62 on page 115 and 116 shows a lot of DDI (Digital Display Interface) and a distinct lot of PEG (PCI Express Graphics -- for some reason that's the Intel parlance for plain PCI Express) pins. So unless you have something connected to the DDI pins, those signals are simply not present in the system.

enter image description here

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