The best way to adjust clock and voltage is through the curve. Press Ctrl+F in MSI AB, click on 0.8V point to select it, then drag the core clock slider (in the main program window) to the right till it reaches ~ 1500-1600 MHz. Then click on the next point (812mv) and drag it down (doesnt't matter how much, it just must be below the clock you set for 0.8V), and then the same for all the other points to the right (they don't have to be all the same clock, just drop them all down rapidly one by one — all of them should be lower than the one at 0.8V). Then click "apply" and you should see a straight line (it might go up a bit on higher voltages, like 1062-1075+mv, but that doesn't matter). That's it, you've got your voltage set to 0.8V and your clock to whatever it is you chose before (should be stable at 1500@0.8V, or maybe even higher, though you still might have to lower it if the miner/driver crashes). Then start increasing the memory clock until you find the maximum stable value (which brand's memory chips do you have btw? check with gpu-z).