Completely negligible difference.

It is best to check whether the mainboard has QUAD Channel or DUAL Channel architecture if you want to optimise it accordingly.

I would go for 2x32GB. Both AMD and Intel currently tend to cause problems with a 4GB configuration.

If 4x16GB, then these must really be 4x16 and not 2x 2x8GB, as these do not work. On my Z790 2x 2x8GB did not work and always malfunctioned.