F3-12800CL7D-4GBRM 1 Pair to 2 Pair problems EVGA NF79

[turbo5546]

So I've been running one pair of F3-12800CL7D-4GBRM on my EVGA nforce 790i Ultra sli board for over a year. I decided to add another pair to upgrade to 8GB of ram but I can't get my board to boot right with the new ram. I had to do some tweaking in the first place to get the ram stable and at the moment I'm running at a clock rate of 1423, only cause at 1600 my system became unstable and below that it seemed unstable too. I Had to put all the timings in by hand cause my board wasn't detecting them right 7-8-7-24 Commands Per Clock is set to 2T. tRRD is set at auto with 5, tRC I tweaked and set to 40, tWR auto at 12, tWTR auto at 18, tFAW auto at 23, tREF at 7.7us and tRFC at auto with 79. My board will not load these values at post when I add the additional 2 2gb sticks so I was wonder what timings I should change and try again. Oh and the voltage is at 1.60v. I've done some research on the problem on the EVGA forums and they guide they suggested for tweaking the rates only lead to my pc not booting and having to clear the cmos. So I did a little tweaking myself and managed to get it to boot most of the time but everytime I got in windows my sound wouldn't work.

[GSKILL TECH]

Try testing each module or each kit seperately to see if the memory is causing the problem.

Thank you
GSKILL TECH

[turbo5546]

I tried the new 2 sticks by themselves and they seem to work fine without any problems.

[GSKILL TECH]

Try increasing the SPP Voltage. The memory controller may be slightly overloaded.

Thank you
GSKILL TECH

[turbo5546]

I upped my voltage to 1.45v and no change, it still crashes in the post after I save to cmos however I tweaked the timming and changed it to 8-9-8-26 and its saving to cmos and posting right. I also dropped the voltage down to 1.35v instead of 1.30 default and upped the ram voltage to 1.65