ya i do CnQ with OCing all the time. On my old X2 3800 I had CnQ through RMClock set as:
2465 MHz @ 1.15V
2610 MHz @ 1.20V
2755 MHz @ 1.26V
2900 MHz @ 1.39V
There's basically 4 things you have to understand with CnQ: P-states, HTT/FSB, VIDs, and Multipliers. CnQ by default has 3 Pstates: Low 4X multiplier with 1.1V VID, mid level, and max at 1.35V (or your VID Max as programmed in the CPU) at your max multiplier with whatever FSB/HTT you set at. With that in mind, this is how I usually get a good setting, using RMClock as the preferred CnQ program (more p-states and voltage+multiplier control).
1. Find out max stable frequency at highest VID available (default voltage essentially) for the CPU at the max multiplier. So essentially you are finding the HTT/FSB you will set for all your p-states. For me, I set my CPU Voltage to 1.35V (although my motherboard will auto overvolt .02V-.04V). Since my max multiplier was 10X on my x2 3800, i set it accordingly. I played with my fsb until i got at a frequency (2900MHz in my case) that I was happy with and left the FSB/HTT value (290) alone.
2. Using the set FSB/HTT that you have from step 1, now find the highest Mutlipier setting that will work at the 1.1V setting. For me 8.5X or 290x8.5=2465 @ 1.1V (added with .05 MB overvolt). This will be your lowest CnQ value.
3. Enable CnQ in the BIOS with the HTT/FSB setting you found in step 1. Boot Windows, install your AMD Processor driver, and set Minimal Power requirements. Reboot and you should be fully stable with your max OC setting. Use a utility like RMClock and you can set predefined p-states as determined by your step 1 and 2. RMclock also does auto VID calculations between your min and max values for intermediate p-states. Personally I checked for stability at each level and tried to push it to the lowest VID possible and programmed it manually in RMClock.
Hope this helps....