There are definitely lots of pre-configured options out there. However, you didn't necessarily mention a budget assuming the owner was open to the idea of upgrading. Either way, independent of the manufacturer, my recommendation as a small computer business owner would be a workstation class desktop PC. I'm partial to the HP Z-class workstations. Below are (2) options:
Option 1
Option 2
Some key points to keep in mind when looking for a CAD type workstation: solid state disk (SSD) for main operating system drive, 8GB memory minimum (16GB preferable), Core i7 or Xeon CPU, and if budget allows, NVidia Quadro or AMD FirePro video card for enhanced graphics rendering. Hope that helps.
It sure is. But looking at the specs you posted, memory is most definitely not your bottleneck. It's that 4th generation i3 CPU you have (circa 2014) which is only dual core. That is a processor that is more tailored for standard home use, not enterprise applications such as ACAD 3D. Newer 2D and 3D CAD applications are now multi-threaded and run more efficiently on quad, hexa, and octo-core CPUs. The i7 and Xeon type processors are prime candidates for this. In addition, it also greatly helps to have supplemental graphics video processing to aid in rendering. A solid state drive (SSD) will also provide night & day difference in terms of program loading and processing performance as compared to that of the older conventional spindle type drives.