The following example illustrates the importance of proper GTL Reference voltage adjustment. Prime95 was run with identical settings in both screenshots except for the adjustment of CPU GTL Reference voltages. CPU GTL Reference was set to default in the first screenshot. From previous measurements this value is 108/110. Prime failed in approximately 47 minutes.
In the second screenshot CPU GTL Reference voltage was set at 112/112. Prime95 ran for almost 13 hours before it was manually stopped.
This article has barely touched on the actual design or execution of GTL circuitry. There are many other factors that come into play affecting the signal integrity of a GTL circuit as well as the relationship of the input signal to the output signal. These go far beyond the level of complexity of this article.
While the brute force approach will satisfy some users, those looking for a maximum stable overclock with the minimum amount of voltages will find GTL tuning a necessity. As should now be evident, there is no dark secret or art to adjusting GTL Reference voltages. With a basic understanding of how the circuit functions and the relationship of the voltages used, mastering these settings should be within the capabilities of everyone.