Everything goes through the Intel GPU -- even if the video data is processed by the nVidia one.   Whatever the capabilities and limitations of the Intel GPU, apply to all video outputs -- both internal and external.  This system does not have a hardware MUX to allow the discrete GPU to directly address a display device.  For that you need the upper end G-series or some of the XPS and Alienware models.  
Hi there, I have Inspiron 7590 with discrete GPU NVIDIA GeForce GTX 1650 4GB GDDR5 and Thunderbolt 3 support. The power adapter is 130W. I'm buying all around monitor,  32'', 4K,  60Hz or 144 Hz, if the system can manage that for gaming? Does video output through USB-C (DP)  deliver full functionality of discrete GPU or are there limitation related to frequency, sync (to avoid frame tearing) etc..  Are there any differences when connecting from USB-C/TB-DP laptop to monitor connection with DP or USB- C  or Thunderbolt. What type of connection should monitor have to exploit capabilities of discrete GPU. Should I buy Dell Thunderbolt Dock - WD19TB to fully exploit dGPU? Is the system (dGPU and USB-C/TB-DP video output) capable to deliver more than 60Hz when playing game. Does make any sense to by 144Hz monitor at all? Considering DELL U3219Q (USB-C, 90W), LG 32UL950-W (Thunderbolt, 60W), BENQU EW3280U (USB-C, 60W),  Gigabyte M32U (USB-C, 144Hz). Please advice, if any not suitable for the Inspiron/dGPU system, when playing games, etc.? Bottom-line, what minimum connections and features mast monitor have, to get the most form Inspiron/dGPU system? Is USB-C video input and 4K,60Hz the best output or should I go for TB connection or also 144Hz monitor? I have read the articles, got the notification of updated TB driver etc., however I'm not sure what to buy that will get the most from the system. ''Dell'' told me to make addition post and mention dell- chris for help? Thanks, Regards,
Inspiron 7590 with discrete GPU GTX 1650 video output capabilities