Page 13 Quad-Core Overclocking, continued

Approximate VTT values and FSB ranges

VTT = 1.2V - 1.3V = Up to 400 FSB

VTT= 1.4V - 1.55V = 420-440FSB

VTT=1.6V (~1.58 actual) = 440-475FSB

found this ,good read for vtt in that article.