I would try 1.5 in bios (with Vdroop/drop- it might result in just 1.45 under load) and what is your FSB term voltage set at ? 3dmark 06 is pretty hard on the CPU, do not underestimate it. Super PI 1MB can ben benched prolly at 4.75 with a high end air cooler and a decent water setup.

I only bench at nite when the ambient is far lower then during the day