Yeah, that sounds good the higher VTT the lower GTL is used, maybe you have looked in the GTL thread, but the REF voltage you have to keep at about 0.8v
and many boards got diffrent values for GTL, I see that you got DFI and they are not the same as mine, that uses multiplier, check the thread, they have the formula for right GTL, and then you can fine tune it.

You got low vNB for that fsb, im needing about 1.50 for 450fsb, but maybe it depends on what other settings and PL you got. Why do you think 1.34 are high? i had my 8500 at 1.45 daily, worked perfectly since it was released, late january until now when i sold it. Ah well its up to the person itself im not blaming you.

Its fun tweaking, but its getting frustrated sometimes

happy tweaking!

regards.