@mos_8502
Higher CPU clock will do the most. Cores will only help if your codec supports a highly parallel encode or if you are doing chunked encoding with many simultaneous encodes.
Chunked encoding will use more RAM as the number of encode processes goes up.
I think it is highly unlikely that the RAM upgrade will be needed nor provide a performance improvement. Unless your current workflow uses all the available RAM for video effects processing it will provide little to no advantage.

The only time I have seen a video encode process use more than 64GB of RAM was a chunked AV1 encode which was badly configured and was running a separate video effects pipeline for each encode process.