i tested for stability in furmark for half an hour but the built in statistic thing said that my core clock was around 1340mhz and then 1320mhz but in games with rivatuner it is boosting up to 1537 and then 1527 mhz, is this normal, thank you for your help because i want to make sure my oc is stable and if in furmark im getting low results i dont know what to do?