Does anyone know what these numbers mean? Its about the RAM. I found these specs...?

Question

What do the numbers mean? 4 - 4 - 8---- 3 - 3 - 8 ...etc.
What do each represent, and what is better, higher or lower number?

The number sets I found when I ran CPU-z. Ive seen them before, and Ive seen people talk about them, but I dont know what they mean. Here is what the numbers are next to...

RAS# to CAS# - 4
RAS# Precharge - 4
Tras - 8

And the other numbers are for another ram piece.

Answer 1

4-4-8 is I believe a faster timing for more performance. 3-3-8 I think is alittle more stable but its still fast. You must be talking about DDR2 memory.