Premiere Pro lagging

That phone media is an issue unto itself ... it's probably long-GOP, which is the single worst media format for editing made. It's awesome in cameras for quick writing of massively reduced files. But it's the way that happens that makes it such a dog for editing.

Because there's only a real, actual video frame somewhere (depending on the device) betwen every nine up to 100 frames or more. Yea ... not kidding! They're called iframes.

In between are datasets of:

• the pixels that will change before the next iframe;
• the pixels that have changed since the last iframe;
• or ... Both.

So to do playback, the computer has to completely decompress and decode up to 100 or more frames, and store them someplace ... RAM or cache files .. simply to show the next frame.

For video players, it's a chore, but all they do is play back one file at a time.

For NLEs, doing editing? They have to grab bits & pieces of numerous files on the fly, do the above mentioned work, and do whatever else the editor calls for. Effects, sound work, whatever.

I work for/with/teach pro colorists, basically all of whom have machines that absolutely freaking dwarf yours in capability ... and they hate long-GOP media. Most of them sort the incoming media from clients, and any long-GOP gets transcoded to something like ProRes before being loaded into the project to grade.

8K RED? No problem. UHD from an iPhone or drone? No way that makes their timeline. They don't have time to waste with it, as they have to do at times up to 400 clips per hour. Including at times masking windows or doorways or subjects or backgrounds, doing 'beauty' work on actors, all the stuff they need to do.