it changes the drivers? or do you mean the driver crashes? run a stress test like furmark after every overclock, and run it for a few hours once you get to very high clock speeds.
iv done burn tests they are all good at +100MHz when i use MSI Kombustor, it reset the clock on
Unigine Heaven and valley, +40MHz is the stable that can do 5 benchmarking tests if i go up 1 more MHz it will reset clock after benchmarking runs