This is, in a way, more of a hypothetical question, not something I'm seriously considering, but I am curious to know how feasible or useful it would be.
The scenario is: The computer has a graphics card with 4GB of RAM in its PCIEX16 slot, as normal. Since the CPU is a Xeon, it has no graphics chip, and therefore the graphics card is the only graphics hardware in the computer.
It would be useful to use the graphics card for video editing (using video editing software that can take advantage of the gpu). At least in Linux, about 600MB of that RAM is already reserved by the system (for unknown purposes). This is a very considerable chunk of the 4GB.
The motherboard also has a free PCIEX4 slot.
Would it be in any way feasible to purchase an ultra-cheap junk graphics card and put it in that PCIEX4 slot, and have the OS run using it, which would ostensibly leave 100% of the big gpu for the video editing software? (Obviously this junk gpu would only be used for desktop usage, not eg. gaming or anything.) Would there even be any real benefit?
Note that the display, and thus the desktop environment, has 4k resolution, so the system must be able to run fluently at that resolution. (Things like running 60FPS 4k full-screen video ought to be possible.)