Virtual reality is in some ways a relatively old concept, but recent developments in computing hardware and software have made this a lot more accessible to a much wider audience. Virtual reality differs from stereoscopic projection, as is common in 3D video systems, in a couple of significant ways.
First, pure stereoscopic projection systems do not account for the position of the observer and how their viewpoint might change. The view is stereoscopic (meaning that it is slightly different from one eye to the other), but the perspective is fixed and does not respond to the observer turning their head or changing position.
In contrast, VR systems recalculate the view as the user moves in the virtual environment which requires both situational awareness through the detection of head position and movements, and efficient recalculation of the point of view based on these changes. Atop this is also the requirement to calculate two separate points of view (one for each eye).
Due to the specific impact of vision on human's ability to balance themselves, it is also very important that there be no perceptible lag between the user's head movements and the redrawing of the virtual reality scene. This generally means a lag of 5ms or less and a frame rate of 60Hz at least for a comfortable VR experience.
Most modern GPUs are capable of achieving these frame rates for one render at a time, and in many cases, this is done by rendering polygons. This is a process that GPUs have been designed to do for many years and are highly efficient at. However, for the use case of visualizing 3D image data, the process of converting voxels to polygons is impractical in most cases and arivis VR relies instead on a method of direct voxel rendering requiring no or little pre-processing of the data prior to visualization.
Because of all these factors, arivis VR requires a high-end GPU to provide a comfortable and useful VR experience, and therefore, the minimum supported GPU is the NVIDIA GTX1080Ti. Newer, faster cards exist and these are highly recommended. arivis typically recommends a minimum of NVIDIA RTX2080Ti, and an RTX3080 or above is preferred.
Note that these are gaming cards, rather than the "professional" Quadro/RTX range. This is because equivalent Pro GPUs that would offer a similar level of performance are typically much more expensive than the Gaming cards we recommend without offering any significant advantages with regards to how arivis VR performs. If your computer is already equipped with a pro card of equivalent specification to these recommended above, there is no need to replace those. Simply, if purchasing a system specifically with VR in mind, gaming cards offer a much better value proposition.
Please also note that the graphics card will need to support the connection method for your chosen headset. if your headset requires HDMI or DisplayPort, your GPU will need that port.