Compatibility between 2 G.Skill memory

[korine88]

I'm wondering if i can use these models together in a z77 system (intel mobo z77 + 3770k)

they have different mhz and capacity

F3-14900CL9D-8GBSR
G.SKill Sniper 8GB (2x4GB) DDR3 1866MHz


AND

F3-10666CL9D-4GBRL
G.Skill Ripjaws 4GB (2x2GB) DDR 1333Mhz


are they compatible, if yes, i'll have some loss of performance ?

thanks

[Tradesman]

It's not a good idea to mix sets, even of the same model - you are suggesting mixing 1333 sticks with 1600 sticks (both of which are native CL9) to drop the 1600 sticks to run at a compatible 1333 they would prob want to run at about CL7....if I were even to try, I'd try at 1600 CL8 with timings of 8-8-8-24, Dram voltage 1.6 and CPUVTT voltage at about 1.17 and with the 1333 sticks in slots 1-3 and the 1866 in 2-4