The old hacked "77" BIOS allowed 1.85v BIOS settings for me, although actual reading was closer to 1.75v. The 39C and 40B were modified by Mr. Natural from the old 77 BIOS. The 7D and 7E are modified by Mr. Natural from a recent official Abit BIOS or beta BIOS. The 7D and 7E appear to be more stable than the previous hacked BIOS files, but the voltage only goes up to 1.7v. I've had the best luck with the 7D of five BIOS flashes I've done. I haven't tried the 7E, but the only difference in it compared to the 7D is additional support for the newer processors (like the 2.4 gig Northy and the Celeron P-4s). The best thing to do is use the 7D or 7E BIOS plus a volt mod such as my VID pin wire wrap.