Use Discrete GPU for External Monitor through Docking Station

@romoguy15  Triple external 4K displays is possible as long as you're willing to disable the built-in display.  (The NVIDIA GPU supports up to four displays, but the Intel GPU only supports three.)  But you can't connect them all to the WD19TB, and that wouldn't be any different even if the NVIDIA GPU controlled the output, because the bandwidth required for triple 4K 60 Hz exceeds the bandwidth of Thunderbolt 3, before even considering bandwidth you'd want to use for any non-display data.  So your third 4K 60 Hz display would have to be connected directly to the system, using something like a USB-C to DisplayPort cable.  Optimus isn't an application.  It's just the name of a technology standard that allows an NVIDIA GPU to do all of the rendering work and pass the completed result over to an Intel GPU for final output to displays that it controls.  Optimus is just part of how your system works, and it's what allows the NVIDIA GPU to accelerate content shown on your displays when needed even though they are technically controlled by the Intel GPU.

@romoguy15  Looking at the Precision 5750's product page, it looks like there's a Quadro T2000 and then a Quadro RTX T3000.  So if the Precision 5750 works like the XPS 17 9700, the reason you don't have that option is because you don't have the RTX GPU.  But if it's any consolation, the built-in display is driven by the Intel GPU too, so anything that works as expected on that display will work the same way on external displays.  There are relatively few use case for giving the NVIDIA GPU direct control of the outputs.  That's typically only necessary for scenarios where the Intel GPU doesn't support the technology you're trying to use, such as VR, NVIDIA G-Sync (or Adaptive V-Sync), stereoscopic 3D, DisplayPort link aggregation (used for running an 8K 60 Hz display by connecting dual DisplayPort interfaces to it), or with that particular system, anything that requires DisplayPort 1.4/HBR3 rather than DisplayPort 1.2/HBR2, since the Intel GPU built into the CPUs used in that system only supports the latter, while the NVIDIA GPU supports the former.  But again those are somewhat rare.  If you just want to use the NVIDIA GPU's rendering performance, that should be available through NVIDIA Optimus even with the Intel GPU controlling the outputs.

@jphughan Not a problem at all. So I think understood your post. I went into my bios settings for display and I do not see a setting that will let me change the output mode. So it looks like it cannot be done. That is really unfortunate as I acquired this laptop for it's graphics specs. Very annoying.

@jphughan thanks for the additional advice. That actually helped.. Really the only thing I want to achieve is triple 4k displays. I'm currently running external triple 24in 1080p thru dockstation. Would I be able to achieve that in my current setup? Is Nvidia Optimus an additional program I can install and utilize further?

@romoguy15  Ok, here is the page of the Setup and Specifications Guide for that system that specifically metnions that option in the BIOS, under System Setup > Display.  Good luck.  Just be aware that you might see a negative impact in terms of battery life, heat, and fan noise.

@romoguy15  (EDIT: I misread the system model initially as Precision 5550, not 5750.  This post pertains to the 5550 and provides general information about dual GPU systems.  My follow-up post below addresses the 5750 specifically.)  All display outputs on that system, even the one that runs the built-in display, are wired to the Intel GPU.  The NVIDIA GPU steps in using technology called NVIDIA Optimus.  A few systems allow you to change which GPU runs display outputs, such as the Precision 5750 and the last few generations of Precision 7000 Series systems, but they can offer that because they have more complex motherboard designs to allow that sort of flexibility.  And some other systems have the external display outputs hardwired to the discrete GPU, which has pros and cons of its own.  Lenovo's ThinkPad P1 that competes directly with the Precision 5000 Series systems works that way.  But your system is the way it is.  I wrote an explainer post around the various ways of designing dual GPU systems and their various pros and cons over in the post marked as the answer in this thread if you're curious.  It addressed an XPS 15 system, but the XPS 15 is the sister system of the Precision 5500 Series anyway, so it all applies.

@jphughan  thank you so much for all this informative information. 

@romoguy15  One other tidbit that many users seem to miss.  When the WD19TB is connected to a Thunderbolt-capable system that only supports DisplayPort HBR2, as is the case here, if you want to run dual 4K 60 Hz displays through the dock, one of them needs to be connected to the "downstream TB3" port at the edge of the dock -- not to be confused with the USB-C port near the HDMI output.  You can use a USB-C to DP cable/adapter there if your displays don't have a native USB-C input.  The other display can be connected to any other output.  The reason for this requirement has to do with how the WD19TB allocates video bandwidth received from the attached system, which varies based on the DisplayPort standard it supports.  But basically, with an HBR2 system, half of the total video bandwidth is allocated to that downstream TB3 port, and the other half is shared across the other ports.  Since each 4K 60 Hz display requires almost half of the total available bandwidth, if you want to run two of them, you have to connect them in such a way that each display gets half of the total bandwidth rather than the two of them having to share half.  Good luck!

I have a precision 7760 which has monitors plugged in through a dual usb c dock. I want to get them to use the GPU as opposed to the intel CPU. You said it is p[ossible on some models, but how is that accomplished?