This is a project I did specifically for my portfolio and is put together in Unreal Engine 4. I designed all assets to work in a modular way so it can be extended as far as needed. All cables are instanced using Unreal's built in spline system. There are about 30 unique assets in the scene. I did not bother with LODs as this is a show piece and not actually going in a game. That being said, with all lighting baked, it actually runs smoothly at 60fps. With real time lighting probably between 30-40fps.
I worked on it off and on while on other jobs when I could get the chance. Took a couple months, but if I were to combine all work time together, I would say it took around 40-60 hours to complete.