two are ocz 1333 7-7-7-20 1.65v other two are mushikin 1333 9-9-9-24 1.5v
if i can mix them, which timing and volt things to follow? thank you so much
Try them on auto first. Then use the mushkin voltage setting, and bump it up gradually if the system is unstable. The lower the voltage the cooler the ram will run. You shouldn't have to adjust timings; let the system select them.