So you're getting your son's old desktop to replace your laptop?
It's hard to tell what you will actually see since there's no info about the video cards but for what I could find out about your laptop the graphics of it aren't especially gaming oriented. Here's some pondering based on the information you've given:
The desktop has a better CPU and lots of RAM so they don't create a bottleneck. As you said you've upped the video card I suppose that part will also be an improvement to the laptop. One very important thing is that the desktop has much better cooling so there will not be a huge performance hit when the components start to heat up.
That said, remember what I said about resolutions and speed in the previous thread. The laptop is 1080p if my searches found the correct models. Your 4k TV will work as a monitor but it has a quadruple amount of pixels to draw so the load is four times that of the laptop. The desktop is not four times better! There's a workaround, though: Simply set the game to run at 1920x1080 and you'll see an improvement to your laptop. Similarly, the Rift S has a higher resolution and also a faster refresh rate which combined double the load compared to the screen of the laptop. The PSVR are even faster so the load is roughly three-fold. So both the 4K TV and the VR you have may end up giving you a worse gaming experience if you run them at their max specs.
