32x64, 16x8, 32x72...?!?!?!

What do these numbers mean, with regards to memory?

When looking for RAM, you might come across something to the effect of:

CRUCIAL MICRON 256MB 32x72 PC 2100 DDR RAM

OR

MICRON/MICRON ORGINAL 256MB 32x64 PC2100 DDR RAM, 184-Pin, CL=2.5-Unbuffered 2.5V

What exactly do those numbers mean :/

The first number is the number of memory banks (in megs). The second its the width of the memory itself (in bits). So 32x64 is 32*1048576*64 = 2Gbit = 256MB.

If it says 32x72, that means the memory has a parity bit (i.e. has some error checking ability).

Usually these numbers aren't very useful. Occasionally you'll find a motherboard that can't support a certain memory density, but that's rare these days.

Memory density specifications so you can tell if your mb supports either high or low density.