Can (should) you mix different types/speeds or ram?

Hello there,

I am building a new system, and I purchase a set of 2x8GB DDR3 1600 (CAS 10).

With the purchase newegg gave me a set of 2x4GB DDR3 1600 (CAS 10).

My question is in terms of performance, would it be better to just leave in the 2x8 set so it can run in dual channel, or will the extra 8 gigs (24 total) be worth it to loose dual channel ?

Thanks!

If you have four RAM slots it means you should have two dual channel banks, so install the each kit in it's dual channel slots and the whole lot will run in dual channel 128bit mode.