mine are NF3-250Gb boards..same as yours?
I use these as backups/test rigs mainly now so it's been a while since I wrung them out.
One is running at 290 right now, with 1.5v. the other one is apart, but I recall it to be about the 285-290 mark as well.
You may need to drop the multi, and perhaps the HT as well
What cpu do you have, and what multi are you using ? Ram speed etc???