Ummm. I have that board for my 939 amd's. I can overvolt and overclock the mobo chipset ram etc. I'm thinking you need an upgrade on that bios. You should be able to get more voltage. This is necc for stable OCin. Also look for some faster ram. DDR500 will have better timings and may increase stability also. But that mobo is outdated. I would try to find a cheap mobo with at least Nforce 4 chipset. Also you can look into volt modding. I'm not sure if that processor will do it and it's dangerous. Use the volt mod ( or pin mod ) as a last resort.
Unless the processor wont let you overvolt wich is every bit possible.