Stuttering on Mac

[Vidventory]

Hi, im experiencing lots of stuttering on my Mac and I have no clue what's going on. Can't recall when the issues started, but it's for weeks, maybe months.

Every 2 secs Premiere Pro stutters and it doesn't matter what I'm doing. It's stuttering during playback, during scrolling, during moving clips, during hovering over options, during writing something. Made a short video to show what's going on: Stuttering of PP on Mac - YouTube

My Mac:

iMac (Retina 5K, 27-inch, 2017)

4,2 GHz Intel Core i7

16 GB 2400 MHz DDR4

Radeon Pro 580 8192 MB

macOS Mojave (Version 10.14)

Premiere Pro is running in the latest Version.

The footage you can see are actually Proxy Files. 720p 1 or 2 Mbits made from 4K footage, so seriously small files. Maybe important to mention these are .mp4 and h264 files. Don't know if it makes any difference.

Have none of these problems on my Windows Laptop.

Hope anyone can tell me what's going on.

Thanks in advance,

Daniel

[Vidventory]

Actually I had to add some information, as I've read it in other posts.

I'm using the build in Drive (2TB), so no external SSD or external HDD. Experienced some issues in terms of speed as it went full, but now I have roughly 100GB left. I'm not a Mac guy, I love my Windows but at work I have to deal with it. Working on it for 9 months now, worst OS ever worked with... but that's another topic.

The files used are smaller than I thought, it's not 720p, I went down to 360p, and to be very precise:

Type: MPEG Movie

File Size: 406,65 MB

Image Size: 3840 x 2160

Frame Rate: 29,97

Source Audio Format: 48000 Hz - 16 bit - Stereo

Project Audio Format: 48000 Hz - 32 bit floating point - Stereo

Total Duration: 00;00;22;00

Pixel Aspect Ratio: 1,0

Alpha: None

Video Codec Type: MP4/MOV H.264 10 bit  4:2:2

Proxy Media

Type: MPEG Movie

File Size: 5,99 MB

Image Size: 640 x 360

Frame Rate: 29,97

Source Audio Format: 48000 Hz - compressed - Stereo

Project Audio Format: 48000 Hz - 32 bit floating point - Stereo

Total Duration: 00;00;22;00

Pixel Aspect Ratio: 1,0

Alpha: None

Video Codec Type: MP4/MOV H.264 4:2:0

Cheers,

Daniel