Dell XPS 9560 i7 , can I run an external Graphics Card? IF so , what do I need?

Thanks for that follow up. I suppose what I meant was that I would continue to run the graphics card in the enclosure and connect that to a desktop. I see a lot of refurbished optiplexes available on amazon and ebay that have been upgraded. They are pretty reasonably priced. But I suppose I would need some kind of adapter for thunderbolt in that scenario? The idea of having a desktop as a back up would be nice if I needed to use it.

@Jamie1989  You'd need an eGPU enclosure and a Thunderbolt 3 cable, the latter of which is sometimes included with the eGPU enclosure.  Note that although some eGPU enclosures provide power to the attached system, the XPS 15 is designed for a 130W power source, which is more than you'll find provided from other accessories because it's actually above the official 100W max of the USB Power Delivery spec.  So plan to keep the XPS 15's own power adapter connected if you want optimal performance.  The only way to get single cable connectivity that would allow an eGPU and provide full power to your system would be to get a dock like the Dell WD19TB.  Dell did something proprietary to allow certain docks of theirs, including that one, to provide up to 130W over USB-C/TB3.  And then you'd connect the eGPU to the WD19TB's "downstream" TB3 accessory port.  But a dock would admittedly be a pretty expensive way to get a single cable solution if that's all you'd want it for.

Beyond that, definitely make sure your system BIOS, Thunderbolt software, and system TB3 controller firmware (separate from the BIOS) are all current.  In addition, I've read that for systems that have a discrete GPU built in, you'll avoid a lot of headaches by matching GPU chip vendor, so given that you have an NVIDIA GPU built in, get an NVIDIA GPU for your eGPU.  That way the NVIDIA drivers will cover both GPUs and handle switching intelligently (e.g. when the eGPU is connected, the built-in GPU will be ignored.)

In terms of limits on eGPU, that would stem mostly from the physical size and power supply capacity of your eGPU enclosure as far as I know.  I don't think there's a limit to the GPU that will operate with your system, although at a certain point you might be paying for performance you won't be using if for example you get a GPU that's so fast that your system's CPU becomes the performance bottleneck.

You can use an eGPU to accelerate content shown on the built-in display, although you will take a bit of a performance penalty there since the eGPU will have to send data back over the Thunderbolt 3 link to your system, as opposed to a solution where you had an external display connected directly to the eGPU's built-in display outputs.  But it should still be a solid experience.

Lastly, you might find the website eGPU.io to be a useful resource, especially in case there are any "gotchas" specific to certain GPUs, certain combinations of GPUs and systems, etc.  The fact that a given set of technology SHOULD work together does not always mean it actually WILL in the real world, so you might be able to find XPS 15 9560 owners over there who might be able to give you some useful pointers.  Good luck!

Thank you so much for that thorough response!

My current gtx 1050 isn't recognized by the computer so I probably wouldn't have a problem running another brand of graphics no?  I planning to stick with Nvidia anyway as their cards are within my budget. Im considering a 1650 or 1660

@Jamie1989  One quick follow-up about your note that you might get a cheap desktop to use this with, which I missed the first time through.  Cheap desktops are highly unlikely to have a Thunderbolt 3 port, which is required in order to run an eGPU.  And they're also unlikely to have a power supply robust enough to support running that eGPU properly if you were to install it within the desktop chassis itself.  There might also be physical fitment concerns there, since cheap desktops might not even have a PCIe x16 slot for that and/or wouldn't have a chassis that would physically accommodate large GPUs.  And even if those weren't issues, a cheap desktop means you might end up with your CPU as the performance bottleneck.  So while an eGPU is a handy way to boost performance of a system, they're not always feasible to use with low-end systems.

@Jamie1989  Without knowing what's going on with your built-in GPU, I don't have a way to say whether that would create a problem with an eGPU.  But my guess would be that of the relatively uncommon things that could happen to render a built-in GPU unusable, few of them would also knock out Thunderbolt.

As to the desktop scenario, Thunderbolt to my knowledge isn't something that can be added to just any desktop with an add-in card.  There are definitely Thunderbolt PCIe expansion cards, but all the ones I've seen have been designed to operate with a specific motherboard or set of motherboards.  It's not like adding a typical PCIe card.  Part of the issue is likely that a certification requirement for Thunderbolt ports is that they support external displays via DisplayPort Alt Mode.  That requires the port itself to be able to tap into either 1 or 2 DisplayPort interfaces driven by the system's internal GPU, and those GPU interfaces aren't available through a typical PCIe slot on a desktop system.  I suppose in theory you could have a Thunderbolt card that had a DispayPort input connector on it, and then you'd feed that from a DisplayPort output on your system's GPU so that the Thunderbolt port itself could pass that through, but I haven't seen that available as a universal solution.  Then again, it's admittedly not something I've looked at in a while, so things may have changed.  But I would definitely suggest doing your research before planning to just drop a Thunderbolt card into a used OptiPlex system.