2500+ xp oc help

[Bigg]

I have an NF7-S mb and 256x2 pc3200, im trying to overclock but no matter what i try i still cant get it to boot, even increasing the voltage to 1.85. Any suggestion? btw, i have OC'd this chip before but ever since ive had dual channel ddr enabled it wont OC

 

[Benny Blanco]

Check the memory timings? Also make sure the memory is set to 3:3, or 4:4, 5:5, 6:6... all the same.