Using two or even multiple graphics cards in parallel has become quite common in the past in order to increase the system performance. nVidia calls this technique SLI whereas AMD is calls it Crossfire. Although systems using SLI/Crossfire might outperform single GPU systems in certain cases, this is not always the case.Why dual GPU setups are not always faster
In order to benefit from a dual GPU setup game programmers need to write extra code for their games to take advantage of multiple graphics cards. Not all developers are willing to invest the time and money into this. Therefore not all games do automatically support multiple GPUs and additional GPUs will be unused while running those games.
Another factor is that most games do not even challenge a single graphics card like the GeForce GTX 1080 Ti. Using two or more GPUs on such games does not bring any noticeable performance gains.Problems with dual GPU setups
Many gamers experience problems when playing games with dual GPU setups. These problems range from random crashes over artifacts to unplayable.Our recommendation
We recommend to go with a single high end graphics card and safe the money for a second graphics card for later. Usually new graphics card generations come with such performance gains that they often outperform dual GPU setups of the previous generation. So instead of investing into a dual GPU setup we recommend to buy a single high end graphics cards and then if necessary upgrade the graphics card one or two generations later.