For a university teaching laboratory with 65 stations that will be used for office tasks, internet browsing, and occasional video playback, 4 Xeon Platinum sockets with 28 cores each would be sufficient. The 3D license would not be necessary for this type of workload.
Here is a breakdown of the CPU requirements for each task:
Office tasks: Office tasks such as Word and Excel are not very CPU-intensive. A single core of a Xeon Platinum socket would be sufficient for these tasks.
Internet browsing: Internet browsing can be more CPU-intensive, but the average user will not be using multiple tabs or streaming videos while browsing. Two cores of a Xeon Platinum socket would be sufficient for most internet browsing tasks.
Video playback: Video playback can be very CPU-intensive, especially if the videos are high-resolution. However, the average user will not be watching videos all day long. Four cores of a Xeon Platinum socket would be sufficient for occasional video playback.
Based on these requirements, 4 Xeon Platinum sockets with 28 cores each would be more than enough for the university teaching laboratory. The extra cores would provide headroom for future growth and for more demanding tasks that may be needed in the future.
The 3D license is for applications that require very high CPU performance, such as 3D rendering and scientific computing. These types of applications are not typically used in university teaching laboratories.
Therefore, I would recommend that you do not include the 3D license. This will save you money and will not impact the performance of the VDI HCI environment.