Try this, These are my settibgs for useing 4 sticks.
DDR volt control=1.55 to 1.6 I would go with 1.6 seeing you have all 4 slots filled.
Trfc 0-3 set @ 160ns
South Bridge volt control = SB/HT =1.4
Not sure how your bios is up on your board but these are common setting on a gigabyte board. let me know how it goes...