[Vengeance RGB PRO not hitting 3200 MHz]

I had the same issue (3900X in Aorus X570 Elite). After googling I have found this solution both here and on LTT forum.

 

- Enable XMP

- Set DRAM voltage manually to 1.35V

- Set RAM multiplier to 32x

- Set the first five subtimings manually to 16-18-18-18-36 (the same as XMP would) (important!)

- Set the sixth timing (tRC) to 56 instead of 54 as XMP would (important!)

 

Has run rock solid ever since.