Ram Issues

[derunds]

I have a Gigabyte z170 UD5 mobo and 2 sticks of corsair vengeance LPX DDR4 2666 ram. This is listed in the compatibility list from gigabyte. However I cannot get the mobo to post in dual channel mode, meaning the mobo will run on one stick in any of the  4 slots, however is will not post with 2 dimms in 1+3 or 2+4. I can get the mobo to recognize 16gigs if theyre side by side in slots 3 and 4. Im just curious if anyone has ran into this issue.

 

Ive :

 flashed to the most current bios ( no change )

 upped Smart Agent voltage ( no change )

 tried both xmp enabled and disabled

 reseated cpu cooler

 loosened mobo screws

 

[dappy10]

have you tried running the ram sticks at different frequencies?