Certified workstation graphics cards are essential for running most modern Cad software applications and without putting too fine a point on it let us start by saying that running Cad software on a gaming card is literally asking for trouble. So bite the bullet and make sure you invest in a workstation graphics card right from the outset as the extra cost is marginal compared to the cost of lost productivity.
Many IT professionals may disagree and more than a few will have built clients a cad workstation over the years with "gaming graphics cards" installed and argue that they run OK. Potentially this could be true (to a degree) if they are only running 2D applications, but even these are not immune from system crashes due to graphics issues and if you are running 3D applications, then this is an entirely different ball game altogether.
The first clue has to be the fact that most cad applications will specify that they will only support workstation graphics cards in their system requirements and if you or your hardware provider ignore that, then you are doing so at your own peril. Let's look at this from a business perspective and a real life scenario that actually plays itself out countless times a year.
Your Cad operator is on a deadline for an important project, their software keeps crashing and they are running behind schedule and getting very frustrated. This has been happening ever since the new computer arrived and it's costing your company money and potential future orders. Your user has contacted software support and they have said that it looks like a graphics issue but are unable to replicate the problem.
Your hardware supplier takes back the computer and does a bench/soak test to check for problems and it passes fine, but back in the office it still crashes. Your very stressed user contacts support yet again and after discussion support ascertains that you are not running a supported workstation graphics card and suggest you change it to see if that solves the issue, but they cannot offer further advice because the card is unsupported.
Eventually (after a few discussions with your hardware supplier) you bite the bullet and have a certified workstation graphics card installed and miraculously the software stops crashing.
The above scenario is a constant in various forms unfortunately. Sometimes because the hardware provider is unfamiliar with Cad applications and didn't understand the importance of cad graphics cards, and sometimes because the buyer thought they were simply saving money.
The fact is that Cad software vendors specify workstation graphics cards for very good reasons so it makes good business sense to follow the recommendations. If you would like to know more we explore this a little more depth in the workstation graphics vs gaming graphics section.