Sorry, I'm new to desktop and currently looking to upgrade my RAM to 4GB capacity. May I ask several question.

1) What is the difference between these RAM and what does "chips" stand for?

KVR1333D3N9 / 2G, 2GB Pc3-10600 DDR3 1333MHZ CL9 (16 CHIPS)

KVR1333D3S8N9 / 2G, 2GB Pc3-10600 DDR3 1333MHZ CL9 (8 CHIPS)

2) I'm using 16-bits Window Vista, do I need to used certain model/series only or is that RAM compatible anyway?

Thax, and sorry for any inconvenience.