It is more a problem with computer hardware not bandwidth. The computer can't process the video at that resolution. I had to get a new computer to even play some of files I record. I have a camera that records at 60 fps progressive and I don't bother using that setting except in rare situations.

Now I have to get a different computer to edit properly. The software I use creates shadow (smaller) files but it takes a while for the computer to create them. When you are working with multiple layers, the computer still stalls in previewing them.