memory - Upgrading my 32 bit Windows 10 Desktop RAM from 2 GB to 6 GB i.e 2+4. Is it less efficient in any way than 8 GB RAM i.e 2+6

I've heard somewhere that the RAM should be in powers of 2 in order to be more efficient, i.e. For example 2GB, 4GB, 8GB, 16GB and so on. So can I upgrade my 2GB RAM with an additional 4GB RAM to use a total of 6GB RAM.