XPS 8930, Dell Update wants to install

It is entirely up to user(s) to decide what's best for them.

For audio driver clarification, The high definition audio device is Realtek audio but currently using a Microsoft audio driver. 

In America, people from the south have a saying, "If it ain't broke, don't fix it"  

@mfurr -  Are you using sound over HDMI to power speakers built into a monitor? That's the reason you'd need to use NVidia HD Audio.

I use desktop speakers connected directly to rear of my XPS 8930. So the only Output option I see on Win 10 Sound screen is Realtek, but Device Manager lists Realtek Audio, NVidia HD Audio, and Intel Display Audio.

Ron, I am using a pair of Klipsh Pro Media 2.0 dektop speakers.  They are not real big but sound decent and all I needed at the time .  They are plugged into the back of my 8930 ' with one cable, in the Green input which connects to one of the speakers and then another cable connects that speaker to the other speaker.  The only things listed in Device Manager under Audio Inputs and Outputs is  "ED273UR Nvidia High Definition Audio and "Speakers High Definition Audio Device".  Those 2 things are all that is listed under Audio inputs and outputs.  Could their be another place a Realtek device might be listed?

I think that Ron was trying to cover all bases and provided all possibilities.  But, in the process, it may caused some confusions.

I've worked on an XPS 8930 before, so I will explain the way I see it.  Edited, sorry as it's a long read.

• The XPS 8930 comes with Realtek integrated audio (on board) and will require proper audio driver for functioning.  Dell provided Realtek High Definition Audio driver and Microsoft provided generic High Definition Audio driver.  Either driver will work for speakers and headphones.
• When you plug the monitor to an add-on, discrete graphics card via HDMI or Displayport, the abilities to carry audio signals over these type of cables also will create another audio driver under Sound Controller.  It will show AMD Audio if discrete card is AMD Radeon.  It will show nVidia High Definition Audio if using nVidia graphics card.  In your case, you connected your Acer 27" curved monitor to your nVidia graphics card.
• A third audio will be available if you plug a monitor to the integrated video of your XPS, using HDMI and/or Displayport.  The integrated video is Intel, therefore, the audio over these cables also listed as Intel Display Audio, as mentioned by Ron.

Beside the Realtek Audio (or High Definition Audio) provides the sounds to the line-out speakers, other audio, when selected, it will send sounds to a TV set or monitor' s built-in speakers.

I hope that all the explanation has helped with clarity over audio drivers and functionality in your XPS.  As for your specific questions "Could their be another place a Realtek device might be listed?" , the answer as from my previous post.  Your Realtek audio is currently using a generic audio driver from Microsoft.  Therefore, it would listed as High Definition Audio.  Also, that was the reason the Dell Update' scan suggested to update with Realtek Audio driver but you chose not to.

If you do want to update your audio driver, download this Realtek Audio driver to your computer.  Double click to run and extract it.  Go to Device Manager, expand Sound Controller, right click on High Definition Audio and select update.  On the update popup screen, browse to the folder with extracted driver and Realtek audio will be update.  Upon the completion, Waves Maxx audio interface will be installed automatically.  Please note, a restart may required to complete the update, you must restart system, so do not run driver update if you are in a middle of something which required to keep the system on.  With Wave Maxx installation, a pop-up may appear, asking which audio is default, you can select Realtek audio, if a pop-up asking for which device was plugged in, select external speakers and changing the speaker size to medium or large (to receive low frequency for better bass).

Alternatively, you can install the downloaded audio driver instead of update.  Just remember to select clean installation to remove all previous audio drivers during the process.  Then again, if something is working well now, you have to decide if you want the driver update.

@mfurr - If the Realtek Audio driver isn't installed, it won't appear anywhere so make sure the driver is installed.

If it still doesn't appear in Device Manager after the driver is installed, you might find an "Unknown" listed. So click View>Show hidden on Device Manager toolbar, and then look everywhere in DM for any Unknown(s). Right-click the Unknown(s) and Uninstall. Then click Action>Scan for hardware changes on DM toolbar and see if Realtek Audio appears. And then configure Waves...