nvidia – Multiseat with PCIe risers?

I am interested in creating a multiseat configuration in Ubuntu.

From what I have read, the simplest way is to have one graphics card per seat (if not, one can user Xephyr, but apparently this creates a new layer of complexity).

I have looked at my B550 motherboard, and apart from a PCIe 4.0 x16 slot, I have a PCIe 3.0 x16 which in fact works as x4, and three PCIe 3.0 x1.

Since my work is basically with CPU, and not GPU, the graphics card is only needed to connect a monitor (in fact, a 4K TV).

I am thinking then in a Nvidia GT 1030. This card is PCIe 3.0 x16, but in fact, it is x4.

I have seen a riser cable 4x to 16x:


So, apparently I could connect a GT 1030 to the PCIe 3.0 x16 (which is in fact a x4) using this riser cable, and not having a loss of performance.

But then, I have thought: couldn’t I have a riser cable 1x to 16x, and connect three additional GT 1030 to the three PCIe 3.0 x1?

In this way, I would have 4 GT 1030, for 4 seats (and I would still have the PCIe 4.0 free).

My question then is: would this configuration work? Not only in the multiseat configuration, but also to show the screen correctly: the GT 1030 is not a fast GPU, but I guess that connecting the card through a PCIe 3.0 x1 creates a massive slowdown.

If I am not going to play games or do video edition, just look at a screen (programming, Excel …) would I notice this reduction of performance?