can't change timings on A7N8X-E

When I try and change the timings it wont boot. no VGA, no beeps, no voice (ASUS voice thingy) just the sound of the HDD going on and all the fans. When that happens I have to reset the CMOS. I've tried this with three different brands of RAM in this board, I also tried the RAM in a A7V333 and I can change the timings. What might be the problem?

You may have to up the voltage a little. Some other people have said you may have disable the voice. Let me know if either of these work.