One of the requirements for Windows 11 is that the processor supports Intel Quick Sync, which is a feature that uses a dedicated video encoding and decoding hardware core located on the processor instead of a general GPU. It enables hardware acceleration in video encoding and decoding, and was available starting with 8th Generation Core processors.
As mentioned elsewhere, many people have successfully loaded Win 11 on 7th Generation processors, and it seems to work fine. However, there is always the possibility that a future update will depend on Quick Sync and then it would be a problem. (Nvidia's parallel computing architecture is called Compute Unified Device Architecture (CUDA) while AMD processors use ATI Stream technology.)