hey there. i have a hd 5570 gpu with gpu clock 600mhz abd core clock at 650 mhz as default. i overclocked it to gpu clock 750mhz and core clock 777 mhz. both the clock has 800mhz max. it is runninf fine n giving me good results. its temp . after overclocking hitting 60c rarely on full load. average it is 55c. so my ques is ,is it safe ??