It's now called BCLK. In the 1156 / 1366 series an increase in BCLK affected memory .... for example if ya increased ya BCLK from 133 to 167, ya memory speed (with the same memory multiplier of 8) went from 1066 to 1333 MHz .... go to a BCLK of 200 and it went to 1600 MHz.
SB is extremely resistant to BCLK adjustments .... most can't get past 103 ....saw one review site that got to 107.5
These guys think that someday peeps will be able to get to 115 .... I have my doubts .... but they explain the math so to speak.http://www.guru3d.com/article/asus-sabertooth-p67-tuf-review/10