(sorry not iPad) I am seeing this CPU utilization issue on my MacBook laptop – in both Safari and Chrome browsers, when I have a tab with the GD content open.
It takes a few minutes to notice the CPU increasing while doing other tasks, but after the fan starts running fast, I notice it immediately, and see the CPU Load rising up to > 80%. and when I switch away from the open tab, I see and hear the CPU utilization gradually decrease to less than 20%.