Crosshair V Formula Z 3 sticks of ram?

Hey i have the manual but i cant seem to find a straight answer on this.

I have 2 sticks of 4gb ram and i have 1 stick of 8gb. i have the 2 stick in there right now but im not sure where too install the 8gb stick. Any ideas?

instal those 4 GB sticks in slot 1/3 and the  8GB in slot 2

dual chanel is mostly slot 1/3  and slot 2/4  pair.  if i was you i would  buy a second 8 gb stick from the same ram, so that you have 2 pairs sticks.  so you can install those 2x8 in slot 2/ keep dual chanel configuration.

So you mean install the 2 4 gb sticks in either the 1-3 channels? (There are 4 channels on this motherboard) then install the 8gb one in the 4th?

those 4gb's in slot 1 and 3 and that 8 gb in slot 2 or 4. but with 3  sticks you dont have a dual chanel config anymore.  as far as that make sense.. ☺

Just stick the 2 x 4gb in the red slots and leave it at that, mixing ram will just lead to all sorts of issues and/or loss of performance.