i have overclocked my gtx 260 on msi afterburner here are my settings 720/1552/1200 it is very stable i have done a stress test on it and get temps at idle 40-50 dregrees c and about 60-70 on full load will it be ok to overclock it to 800mhz, it wil ok like this 800/1725/1200 will it be safe or do you think it will cause my motherboard or any other componants problems, btw my phenom ii 965 is overclocked around 4ghz

Anytime you overclock a component you are risking its usuable lifespan. Even if you are able to combat the increased heat through more powerful cooling solutions there is still the fact that the internal stresses are greater than what the component was originally rate for.

If you are stable at 720 you can keep going, but stair step your way up. I usually working 5-10MHz steps, so your next step would be 725/730. Keep slowly bumping it up and it will be easier to find the overclock ceiling on your specific card.

My method is: put clock to max

stress test it, if fail, step down clock,

repeat untill you found stable clock.

That is one way of approaching it. Are you testing each clock separately? I.E. Test GPU Core, then Test GPU Memory, then Shader etc?