Are you able to undervolt Phenom from the bios?

Previously I had a Celeron 600@675 1,4V running in a Compucase desktop case and the only exhaust fan was the 80mm Nexus 5v in Zalman 400w ps. Celeron didn´t play all the divx files without skipping. So I swapped the CPU to P3 866MHz. Pentium is doing fine at 1,4 volts with AMD-boxed hsf. Speedfan is...