OK to clarify this even more, no it is ridiculous to say you will need double the ram to cover an increase in data bus.
There is *some* validity to the statement though: computer's consist of millions and billions of bits, and whenever they process a command they have to process the entire data bus.
If you are familiar with programming you may know the following data types:
char -- a 1 byte (8 bit) value
short -- a 2 byte (16 bit) value
long -- a 4 byte (32 bit) value
*note: considering none of these data types are signed
but where is the oh-so-famous int (abbreviation for integer)?
Many, many, far too many programmers do not know the answer to this, and with proper reason. What size is int? Many programming books when you read them just say, int can be of different sizes, and are never really clear why, and where it gets its size from.
The answer is your question: int is the size of the data bus. So a 32-bit processor int would be the same size as long, but a 64 bit processor would be the same size as a double long.
So when you run some programs on your computer, many programmers use the data type int to avoid running into problems with processors and because, well it's easier
BUT, because of this reason, your computer will be using a bit more ram, but far from double.
Hope that cleared things up!