This is what I did.
I started overclocking by raising the FSB.
The moment I had a no boot, I raised one click each one volt, then I checked all combination of volts, until I had a boot.
In case I still had no boot I checked raising volts, one by one and in cominations, by two, three clicks etc.
This is what I found about GTLref.
http://www.xtremesystems.org/forums/...postcount=1095