Playback within Premiere poor/pixelated after render

Hello All,

I have browsed the forum for answers to my issue but have had no luck so apologies if this has been answered elsewhere. I am really struggling with this so any help would be appreciated. I am usually one for getting stuck into Premiere and finding a resolution myself but I just have hit a dead end with this one...

I am working on a new project in Premiere Pro CC 2018 (12.0.0). I have some footage filmed on a Canon C100mkii (1920x1080, 59.94fps) - in the timeline, looking great in the source window - and also looks fine before rendering in the timeline! Once I render this footage in the timeline I am losing quality and getting some pixelation - I cannot for the life of my work out what is causing this?

Some info for you:

• Playback resolution is set to full
• High quality playback selected in program window (right-click)
• Video rendering and playback (GPU Acceleration CUDA enabled)
• Capture format: HDV
• Sequence settings: Editing mode: AVCHD 1080p square pixel, Timeframe: 59.94 fps, Pixel Aspect: Square 1.0 (I have not adjusted these settings, I am assuming this is what Premiere has selected from the footage that was used in the timeline?)
• This is simply within Premiere itself during playback. I am not doing anything different to my workflow in previous versions of CC.

PC Spec:

• Intel Xeon E5-1630v4 @3.7ghz
• 64gb Ram
• Windows 10
• Nvidia Quadro P5000
• x4 healthy SSD's split between OS, Previews & Exports, Media Cache, Projects/Media files

Once again, apologies if this has been addressed and answered elsewhere - I did have a good hunt around for a solution. If anyone can offer me any tips/things to try then I would be hugely grateful.

Thanks,

James