Render output is laggy when clips are 4k 60fps

[Antônio5EAC]

I am rendering a movie in H.264 and some parts of the render (which work fine in preview) are lagging.

I've identified that these parts are some of the drone shots recorded in 4k60fps. The final output of the movie is Full HD (1080p) and 23.976fps.

I have also already tried the standard recommendations for these kind of issues: disabling hardware decoding (and coding), changing the general preferences for using only Mercury instead of CUDA, and trying both Hardware and Software coding options in Video section in Export Settings. Also cleaning cache files. All of these options using Media Encoder (but also tried in the new Export panel with software coding and nothing changed).

I am not using proxies, and I have rendered this movie before, but with a previous PC configuration before I have recently formatted.

My PC specs are:

Intel Core i5-10400F 2.90GHz

32GB of RAM

NVDIA GeForce RTX 3060 Ti (Studio Driver 528.02)

Windows 64 bits

Previous render PC specs:

Same processor and OS.

16 GB of RAM

NVDIA GeForce 1650 SUPER (Studio Driver)

[Antônio5EAC · Accepted solution]

Well, I guess it's solved. I think the first time I've cleaned the cache files, I have not selected the clean ALL option. So the solution was to clean it all again, but now selecting both options. Still, I am very upset that I had to go through this whole journey to solve this mysterious problem, which should not at all be present in a software such as Premiere. I have been working with it for years and I am now seriously considering moving to another software such as DaVinci.

[MyerPj]

The reason that feature is in there is so you can use it. I'm surprised that "have been working with it for years" and never had to use that. I use it each time there is an upgrade. Actually I do it manually:

Delete your cache files as follows. (Close Premiere Pro) 
The files are located here, Paste the whole line below into File Explorer:
%UserName%\AppData\Roaming\Adobe\Common
Simply delete the three folders:
•• Media Cache
•• Media Cache Files
•• Peak Files
Premiere Pro will automatically create the folders and files it needs as you edit. I do this before every upgrade. And/or if things seem to go strange. I also keep a desktop shortcut to this folder for quick access.

[Antônio5EAC]

I have used it before, I just forgot to test with it when trying to solve the issue.