Since a laptop thread got me thinking about it, I’m posting a quick desktop build to demonstrate how inexpensively you can run CAD on a desktop PC.
Ryzen 3 3200G processor ($95)
8 GB (2x4GB) G.Skill Ripjaws V DDR2400 Memory ($44)
Crucial 500 GB M.2 SSD ($70)
MSI PRO B450M Micro ATX Motherboard ($75)
Rosewill Micro ATX case ($41)
Thermaltake Smart 430W power supply ($38)
That’s a $363 desktop box that runs Inventor very nicely. The one I run at home is really similar to that build. I’ve thrown a lot of decent sized robot models at it, and it handles them very well. The Vega 8 graphics with the Ryzen cards get the job done. I really like Ryzen 3 at its price point when its integrated graphics (better than Intel’s) are taken into account.
Used HP Z series workstations a couple generations back can be a great value too. I’d recommend looking into Z420 and Z230 lines. They were available with a wide variety of configurations, but often they were pretty well spec’d for media companies.
Inventor likes VRAM on the video card, and can definitely soak up regular RAM as well. Would be worth the money to jump up to a 3100 or 3300x (Inventor is largely single threaded) and 16GB of RAM. Total system cost should be ~$500 with a 3300X, 16GB RAM, and a RX570 with 8GB of VRAM. Would be a substantially faster machine for not much more money.
Alternately - you can do a very similar build to yours in the AsRock A300 Deskmini and have a tiny form factor. ~$150 for the barebones, add RAM/CPU/SSD. Price comes out to ~$350 with the same specs, and it’s a 6.1" x 6.1" x 3.15" box.