If it resets to default immediately, you may be unstable or there's something wrong with the program.
If it resets every time you start up your PC only, you should tick the "Apply overclocking at startup" option at the bottom of the OC sliders' screen.
I got GPUTOOL and ran the test function where it brings up the image that taxes the GPU, and ran that for about 30 minutes with 0 errors.
And i do have that option ticked but for some reason it wont apply at start up either. I have to delete my save profile, shut MSIA down, Reopen it, Reset my clocks to what i want, and then they hold but for only as long as my system is on. I also open gpuz and restart it occasionally to be certain if my clocks are set or not.