Gigabyte boards are not very good OCing wise in general. They have great stability but won't push your cpu to the max. That said Pentium Ds OC best on the higher end 965p boards. If you can still find them I would recommend the P5B-Deluxe.
What are you smoking? Gigabyte boards are GREAT overclockers. Maybe you won't set a world record on them but them and ASUS are the absolute best for what most people are looking to do. Had absolutely no problem OCing my Q6600 to 3.2Ghz on my P35-DS3R. I can take it to 3.6Ghz and have done it but prefer to keep it at 3.2Ghz.
That being said, the only time I've ever had bios OC settings reset during a reboot is if my OC settings weren't stable, the board automatically reverts to a known working bios setting if what you set isn't stable.