See, easiest way in my experience to do this is to run MSI afterburner and Heavens benchmark. Put the benchmark, while it is running in the background and bring the MSI AB app to the foreground. Increase the clock slider by say 10 MHZ and let the benchmark run. If it completes, let it run one more time. On the third run, repeat and increase the clock by 10 again and repeat the process till the benchmark crashes. After that, dial it back using the same process till it no longer crashes.