Best software for OC of Nvidia chipsets?

The best way is through the BIOS, though don't expect to get much of an over clock. Nvidia 6 series chipsets are notorious for getting hot because of insufficient cooling. I was barely able to get to 4 Ghz stable on an E8400 with a 680i SLI motherboard, and this is with the NB idling at 55 degrees Celsius.

How hot is to hot? Case cooling should not be a problem, 2 exhaust fans and 1 intake. Big copper cpu cooler 120mm fan on it. removed the motherboard heat sinks and redid the thermal paste. I don't trust the Nvidia system monitor. Is there a better thing I should use? I think its ready to be juiced up a bit. Do you know of any settings that worked good for you. I've had it at 1544MHz FSB and CPU @ 2.7GHz ram @ 900MHz but it seemed to lag some. Tried to set it back to stock speeds, it would not do it with out "the blue screen crash dump restart over and over" reformatted vista32bit and it was good again. IDK!!!

Too hot is the 65 C region, make sure you don't go above that and you'll be fine. As for the settings I used, I bumped up the RAM speed to 1000 MHZ and set the FSB to 430 MHZ, with the V-core set at 1.28 volts. I was able to get to 4 Ghz stable, bu that required an excessive .12 volt increase. The FSB, NB and SB voltages were kept at the lowest settings.

Remember to run P95 for atleast 24 hours before assuming it's stable! Also, make sure the CPU doesn't exceed 65 degrees C when torture testing.

EDIT: I forgot to add that I experienced instability when I left Speedstep (or whatever it's called) on.