It's down to the GPU chip on the machine, and the amount of RAM the GPU has. Unless you're driving a large screen (4K+), you're not going to see much advantage with it anyway. In fact there are machines where it slows down the process because the files have to be converted from the CPU to the GPU and this negates any benefit from using the GPU.
Thank you for taking the time to answer. I was never actually dis-satisfied with the response time. The only thing that happens periodically is when ever I have my pen or mouse on a slider to move it the image gets blurry on the screen till I have made the adjustment. Not sure how to correct that.