The CPU and GPU do not perform computing in the same way. You would have to specifically write a program to be able to utilize a GPU. Most software companies have a hard enough time writing software that properly scales across multiple cores, especially when it’s more than 2 or 4. CUDA might be the easiest, most accessible way to take advantage of GPU power to perform computing, but it’s specific to Nvidia, and you still have to make tasks run in parallel.