two sticks works four sticks no work

[kof2000]

i'm trying to installed 4x256 onto this other rig which before has like 2x256 on dual channel and then it was working find, now i installed 2 more of the same type/brand into the other two slots and computer kept restarting and goes to the black screen boot to safe mode and stuff. i tried taking out the first two and install the two new one and it works so it is not the slots .

 

[kof2000]

i know it is not faulty memory other than a mobo compatiblity since i've tried all the ram on another computer and it works and all different combinations of the slots the slots works but once all slots are filled the video card is not displaying the contents.