I don't have native 1066 memory either. All of my ram kits are gmh's 3 G. SKill 6400 HZ's & one Crucial 25th Anniversary. I also have some Cosrair 8000UL's, but none helped the second board hit 500FSB or the first get past 509FSB. I'm gonna go ahead and order some Crucial PC8500's and see what happens.

yenclas
we have the same ram but I put 2.25-2.3v on mine depending on the FSB. I've not run less than 450FSB on this board so I've not set vdimm to anything lower than 2.25v. I don't get any hard locks like you're experiencing until I get above 500FSB. Again it sounds as though you have something set too tight. What do you have tRFC set too? If auto, try 35 or 42. I have one kit of G. Skill 6400 HZ's that can do 1066 with 2.25v but on this board they didn't do squat above 500FSB.