i have some problems with my RAM F3-10666CL7D-4GBRH, CL7 @ 1,5 V
here are my pc specs:
Mainboard: Asus Rampage Extreme II
I tried many settings to get the GSkill RAM working @ 1800mhz
What I could find out:
 Memory Voltage,  NB Voltage,  Timings
 1,5 V  1,5 V  10-10-10-28 => works finde
 1,5-1,56 V  1,5 V  9-10-10-28 => Memtest86 errors
 1,58 V  1,5 V  9-10-10-28 => Memtest86 freeze
Its very hard to complain for me that i can't overvoltage this memory! I think there must be better timings on higher voltage but i dont know why. I tried a lot with different NB Voltages but i can't get it working.
Maybe some 1 got some experience with a similar problem and can give me some suggestions how to improve the timings with overvoltage
 1,5 V  1,48 V  9-10-10-28 => errors @ memtest
 1,5 V  1,48 V  9-10-10-27 => runs fine!
I am very confused because I thought
Row Active Time (tRAS) – This is the minimum number of cycles that a row has to be active for to ensure we’ll have enough time to access the information that’s in it. This usually needs to be greater than or equal to the sum of the previous three latencies (tRAS = tCL + tRCD + tRP).