How much can i safely overclock my GPU?

I used ntune to move my memory bus and core bus up 100 Mhz and i saw major improvement and now im wondering how much further i can go with out puting my computer in serious danger. What happens when i go too far? and also how come nTune doesnt save my settings?

UPDATE: I ran a stress test and the results are just the number of passes completed, What the hell does that mean?????

You should overclock your GPU by 10 - 10 MHZ or less and keep checking its temperature and making stress tests at each overclock you make,btw and make sure you have a good cooling system.

If you push too hard without checking the conditions of the GPU u can get it burned so be careful

If you push too hard without checking the conditions of the GPU u can get it burned so be carefulneom22

Burned? No.
Start artifacting and/or freezing? Yes.

Artifacting and freezing is easily remedied by decreasing the clocks, increasing the voltage, increasing the cooling or by restarting your system, if frozen.