Using more memory slots?

[castlechef]

I am building my first computer, and as with most new motherboards it has 4 ddr3 ram slots capable of holding 32gb of ram. I only really want 16gb, at 1600MHz, so should I make the most of all 4 slots and buy 4 4gb sticks or 2 8gb sticks? Does using double the number of slots double the speed of the ram, so instead of having 2x1600MHz I could have 4x1600Mhz? Also would it be worth leaving 2 free for leaving room for future proofing?
Thanks!

 

[dingo07]

how do you come to the conclusion you need 16GB of RAM?
what version of windows are you going to install?
is your motherboard quad channel memory compliant, or just dual?

 

[Randy Appo]

Quad, Tri Dual channel takes advantage only when all RAM slots are occupied, i dont know what real world differences will be though

 

[c_for]

I recall reading a benchmark regarding this issue a while back. I can't seem to find it right now but it showed that 2x8 is faster than 4x4. But it is only slightly faster. It's a small enough lead to not be noticable. But even besides speed you should go with 2x8 incase you want to upgrade later.