which graphics cards does MacBook Pro (Retina, 15-inch, Mid 2014) have? from "About This Mac" I see that model is "MacBook Pro (Retina, 15-inch, Mid 2014)".
From my understanding technical specifications page (https://support.apple.com/kb/SP704) for MacBook Pro (Retina, 15-inch, Mid 2014) lists two graphics cards for that model:
Graphics and Video support


Intel Iris Pro Graphics
NVIDIA GeForce GT 750M with 2GB of GDDR5 memory and automatic graphics switching


I can't find any evidence of GPU "NVIDIA GeForce GT 750M" in the system.


About This Mac shows only "Intel Iris Pro 1536 MB"
System Preferences -> Energy Saver doesn't have "Automatic graphics switching" option (according to https://support.apple.com/en-us/HT202043: "If you don't see the automatic graphics switching option, your computer has one graphics system. To confirm, choose Apple menu > About this Mac, press the System Report button, and select Graphics/Displays on the left. The graphics system or systems are listed under Video Card.")
About This Mac -> System Report button -> Graphics/Displayes on the left. Again, I see only "Intel Iris Pro Graphics"


It rather looks as my Mac has only one graphics system.


am I right that my Mac has only Intel Iris Pro graphics system?
if there is only "Intel Iris Pro" in my Mac how is that possible that official technical specifications page https://support.apple.com/kb/SP704 also lists "NVIDIA GeForce GT 750M"?
Apple sold many different versions of the 2014 MBP - different SSD sizes, different RAM amounts, different processors, and on the most expensive machines, a dedicated graphics card.

You may have a machine with only integrated (Intel Iris Pro) graphics. To learn whether or not you are right about only having integrated graphic, you need to know the exact MBP model you have.

One easy way to determine which model yours is:


Go to the Apple (top left of screen) and choose "About this Mac".
Look at the pop up window and find the serial number listed at the bottom. Copy it.
Go to www.everymac.com/ultimate-mac-lookup/ and paste your serial number where it says Enter Identifier.
This will bring you to a page with the model of your machine. There you can see all of the specs. If the name has a (DG) after it, then you have a model with dedicated graphics. If it has an (IG) after it, you don't. This is an example with dedicated graphics: