8 GB ddr3 1866mhz 9cas VS 10 gb 1600mhz 11 cas?
UPDATE: I added some details
So I have 4 slots dual channel supported (z97x killer mobo and i5 4690)
I originally have 2 4gb sticks of 1866 ram in the dual channel ram slots (1 and 3).
I was able to find a spare 2 gb 1600 stick so I added that...