CUDA cores are the processing units found in NVIDIA graphics cards that enable parallel computing. They allow the GPU to perform many calculations simultaneously, making them ideal for tasks like rendering graphics, running simulations, and performing complex mathematical computations. Each CUDA core can handle a small part of a larger task, which significantly speeds up processing times compared to traditional CPUs. This parallel processing capability is particularly beneficial in fields such as machine learning, video editing, and scientific research, where large datasets and complex algorithms are common.