Rendering slow

Steps to reproduce:
    1.render project created with 14.6 ...

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Background Info

Tried 14.8 because 14.6 randomly failed with Error : Selector 9 

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Result: ectremely long render time compared to 14.6 (twice as long)
Expected: at least the same time to render
 
System info
    Application: Adobe Media Encoder (Beta) v14.8.0.12
    OS: Windows v10.0.19042, RAM: 31.94 GB, CPUs (logical): 24