I want to overclock my i7 930 to 4ghz and looking for the best possible way to get the voltage as low as I can while it running stable at the same time and I'm wondering what Ratio Muiltiplier and Block is best for this? Is using a ratio of x21 with a block speed of 191 better for stable overclocking with lowest possible voltage? or is using a ratio of x20 with a block speed of 200 better? I've also noticed between these settings that the ram frequency for the x21 option is 1520mhz and the ram frequency for the x20 option is 1600mhz (due to higher block speed) so I'm sort of leaning towards the x20 option because of that. But any advice about what is a better stable option between these two settings to help me decide what option I should stay with would be appreciated.
The only way to determine that is to try them out and see which one works better with the settings. Every board and chip combo is going to be different. Set up and run one scenario with low voltage, when it blue screens check the screen and you should get the 0000101 code which means not enough voltage. Bump it up slowly until it runs stable. The other code to watch out for is 000124 code which is the QPI/Vtt needs to be increased or decreased. As far as the memory goes you should be able to change the memory multiplyer for some adjustment if you find the 21 works better. Normally you would reduce the memory speed before attempting an overclock to help it run stable. After you get it that way then you start working on the memory.