It is. I had a subscription and used a Roku Ultra. However, I cancelled my subscription after every 4k stream buffered even on a gigabit connection. I watch 4k

It is. I had a subscription and used a Roku Ultra. However, I cancelled my subscription after every 4k stream buffered even on a gigabit connection. I watch 4k UHD content on every other service through the Roku without issue. So your mileage may vary.