How you OC, and what ATI driver you use
I am using polaris bios editor to copy 1500 mem strap all the way down to 2000 as one rom and then I create another rom copying 1750 down to 2000. I then use atiflash as admin via the command prompt to flash those roms. Of course I restart after each rom. I've already patched the drivers so they are recognized by windows. Then I will see if I can add more hashing power by making adjustments in MSI Afterburner.
you can also use mining-ready operating systems as simpleminingOS or ethosdistro. in these systems OC is easier than windows.
I've tried simplemining os and it doesn't overclock for me.If you're using latest 17.7.2 driver, you can only OC through wattman or latest beta afterburner (4.4 15 or something like that)
Also, using 1500 strap could be too aggressive
