Pixelated and low quality 4K footage, preview, playback and export in premiere pro

[Rosemary M]

Hi Everyone

I was wondering how much my computer could affect Premiere's capacity? 
I've been working on one project for a while and recently switched the MacBook I was working on. The MacBook I'm using now is lower spec but should be good enough to operate premiere. However I'm encountering problems I didn't have before: on the clips I have edited and colour graded on the new MacBook, the quality is appalling, the whole project was shot on the same camera but the clips I have gone back in to edit are previewing at extremely low res in the preview window and are also exporting pixelated and with clunky colour blocking. I am not having this error with any of the clips edited on the higher spec MacBook. I feel like I've tried everything to fix these issues and as there is such huge discrepancy within the project itself I was wondering if the reason could be a low spec computer? Would love any help with this as I have been battling it for way too long now. Cheers!

[LinSims]

Let me move this to the Premiere forum for you, where you are more likely to receive an answer to your question.

The Community Help forum is for help in using the Adobe Support Community forums, not for help with specific programs. Product questions should be posted in the associated product community.

[ah_photo]

Playback quality and quality after export usually should be different, but it shouldn't vary based on the computer itself.

Playback quality is determined by the playback resolution in Premiere. Export quality is determined by your export settings. What are you using for export settings? If you're using a lower spec computer, if anything it should just make playback or encoding slower / more sluggish.

Secondly, just because you mentioned switching computers, you didn't do something like JUST move your proxy files over and not original source media did you?

[Rosemary M]

Hi, thanks for your response. 

All files have been stored on the same external hard drive so they haven't been moved about at all. I've been using preset H.264 for export settings, selecting maximum depth and maximum render and 68bitrate. 

And yeah I'd agree that if it was the computer I'd expect it to freeze or crash in some way. But I can't really understand what else it could be. Premiere does seem to operate fine on the computer, it is a bit slow but other than that it's fine, the export time for a 6GB file is about 7 hours. 
I can attach screenshots if that's helpful?