acceptable cpu voltage fluctuations?

Hi all, I have been trying to work on my OC stability. My swiftech NB did not stay on well because of a cap in the way, so I am trying a NB-1 with arctic silver adhesive. The overclock I am trying to keep stable is 240fsb 1:1, 1.7V CPU, 2.8V Memory, 1.6V AGP. Sometimes it runs great at full load for a day and sometimes it will just restart. So I look at my voltages. Speedfan reports it up to 1.71 and as low as 1.65 idling. These are the same readings I get In the system BIOS.

1. Are these acceptable fluctuations?

2. Does the BIOS control CPU voltage directly (should I try flashing to a different verion?)

Thanks for the help feel free to post any questions you need to help me out. I have and antec 430 True Power which I will swap in tonight if i find the time. Thanks.

Okay, the Antec 430 is hooked into just the MB and CPU and speedfan is reporting cpu voltage at 1.66 full load and 1.71 idle. After it runs for a while I am going to hook the True Power 510 in the same configuration.

Swapped back in the PC Power and Cooling 510, and speedfan says 1.66 full load, 1.71 idle. So I guess this isn't the problem. Both tests were used with CPU fan, CPU, MB and 1 Hard Drive connected. I guess I will just keep upping the voltage to get a stable 20% or do you think i should trim back the FSB and give up? Any votes for popping of the NB-1 and using arctic silver adhesive on the Swiftech?