This message was posted on behalf of Intel Corporation1 of 1 people found this helpful
In regard to your questions, it is all related to compatibility.
In order to make sure you will be able to play an HD video on both the laptop screen and the HD external display, the best thing to do will be to get in contact with the manufacturer of the laptop and the manufacturer of the HD external display, to verify all the specifications on each of the components.
We had cases where some customers were able to do that, we have other cases where the components are just not compatible, but in theory you should be able to it, also previous drivers allowed this type of configuration as well.
So, if you are interested in the Dell® xps 13, then the next thing to do will be to get in contact directly with Dell, they might have a list of external displays that are fully compatible with the laptop and also all the requirements or specifications that are needed so you can make sure they will work just fine together.
I saw that there are different versions for Dell® xps 13:
All the processors showing in there work with Intel® HD graphics 620, and on the following chart you will be able to confirm the resolutions they support under "graphics specifications", and also you can confirm they support up to 3 displays, so the integrated graphics are suitable but it is up to the customer if he/she prefers a laptop with discrete Nvidia graphics, in that case in order to find out the information about those graphics you just need to check that with Nvidia directly.
But remember, that the manufacturer has the option to customize their products, so they can enable or disable some features that is why is always better to check directly with them:
Dell’s phone number: 1 800-624-9897
Dell’s support site: http://www.dell.com/support/home/us/en/04
In regard to the 4K resolution, you just need to make sure the external display supports 4K resolution, as you can see on the chart above the Intel® HD Graphics 620 supports it, but depending on the processor there might be some limitations for dual display.
On the following link you will see the technical product specifications for the processors listed on the link above, please check page 38 and 39 for multiple displays resolutions, look for U processor, as you can see it is also related to memory:
Any further questions, please let me know.