4 sticks 2x 8 and 2x16, i did have a problem at first, where the machine was running in single channel, windows would not use all the memory and the ram speed was set slow. i took the memory out and changed it around and it worked. But i think the problem was I did not press the memory down hard enough into the slots, so it was half in and half out.
All corsair Vengeance LPX memory and works fine runs in dual channel, proper speed, and Windows recognises it all and uses it all.
That config should be fine and work in dual channel if you set it up as
channel 1: 1x8 + 1x16
channel 2: 1x8 + 1x16
Basically each channel has to have the same amount of memory and also the dimms effectively mirrored in the slots