Even the older versions work pretty well, depending on the features you need. I use it for all my 3D modeling, I could never get the hang of other CAD software but this one just “makes sense” to me. I even used it last year to create a model of a trailer I wanted to build, worked out the finer details of how everything would fit together and some options like adding ramps, and once we got to the point of building the trailer it was just a matter of copying the dimensions and cutting out all the steel.
If your card has an x4 pinout, then it probably needs the additional bandwidth. Plugging it into an x1 slot (if it was possible) would slow down the network traffic. Get a better motherboard with an x4 slot on it so you can use the hardware you want. or find something else that will fit your computer.
Honestly even the 1Gb quad port card I have requires an x4 slot, although I saw some dual-port 2.5Gb x1 cards on ebay. Maybe you could just use two of those?