Not that simple. 4 dimms were getting higher clocks on 2 CCD Ryzen models (12 & 16 cores) compared to those with one CCD. Motherboard topology is a factor too.
But there is no single configuration where having 4 DIMMs populated gives higher speeds than when 4 DIMMs are populated on the same configuration. This is because while the higher end parts tend to have the higher binned components they still inly have 1 shared memory die between the CCD and the motherboard topology is either it has 4 slots or it doesn't, but no matter how they are ran it's still better to only use 1 rank of each channel.