Which mobo do you have exactly, and which memory do you have exactly? I see two 780i mobos on Newegg. One has a memory standard of DDR2 800, and the other has DDR2 1066 up to 1200MHz. If your mobos memory standard is DDR2 800, then this could explain why you're experiencing this.
I ask because my mobo's memory standard is DDR2 800, and I have DDR2 800 memory installed. I cannot get it stable past 952MHz with the timings I want, which are 5-4-4-12-1T. Yep, 1T.
But I don't care, because I read somewhere that with the nForce chipset, it's more important to get the tightest timings possible, and then increase the clock. But with an Intel, it's overclock first, then see how tight you can get the timings. But, I have no way to know if that's true.
I also don't care because I've found that 1T vs. 2T is noticeably faster. And with a 152MHz overclock on 1T, I couldn't possibly be happier.Edited by TwoCables - 12/26/08 at 3:25pm