Slow lagging playback Sony footage

[CountSleep]

I just started working on a project with about 900GB of footage in which all of it was shot on Sony cameras, some Venice and the rest FX6. The footage is 3840x2160, SLog3 Cine, XAVC codec. The issue that I am having is that when I try to play the footage in the sequence or the source window there is a several second playback delay. And if I scroll or move around in the sequence there is a seconds long lag before it gets to the frame I have moved to. Lowering the playback resolution has no effect. And Premiere is not in the midst of creating peak files — it already completed those. 

I am able to playback comparable resolution footage shot with other cameras just fine. And I am able to play the same Sony footage in Davinci Resolve with no playback issues. So this is not an issue with the computer or hard drive not being fast enough to play high res footage. 

The footage is stored on a fast SSD Thunderbolt 3 drive. And I am using a MacPro 2.5 GHz 28-core Intel Xeon, AMD Radeon Pro Vega II 32GB gfx card, with 192 GB RAM. I am using Premiere version 24.1.0.

I just wiped this computer at the end of November and have only edited a couple projects since then, so there are not a lot of cache files or anything like that floating around. 

The only plugins I have installed are Red Giant Universe and Digital Anarchy Flicker Free. I have the most recent version of both plug-ins and I am not using them in this project. I haven't even started editing yet, merely started organizing the footage. 

I am hoping to hear of a solution here or otherwise I'll have to edit Sony projects in Resolve going forward.  Yikes!

[R Neil Haugen]

Have you set the default audio input to "none"? That has actually improved playback for a number of users.

[CountSleep]

Thank you for this suggestion! I just tried it and unfortunately it did not have an effect. 

I also tried pressing Alt when launching Premiere and selecting all of the options listed. It remade all of the peak files, but I am still unfortunately having the same issues. 

[Ground Films]

Hi, was this ever resolved?

[R Neil Haugen]

How do we know you have an identical issue to what the OP had? They gave wonderful depth of details to see what was going on.

And you may have something that appears similar but in reality is different in the cause.

So either give full details for hardware, all media & effects used ... here, or in a new thread specifically for your case.