Whenever I start up DiRT Rally, my GPU (GTX 960 SSC) is at 1392mhz with 90-100% usage but then after a while of gametime later (10-30) minutes later, it sinks down to 5% and 1278mhz. Makes no sense why it does that mid game and it gets really frustrating by going to 60+fps down to 30>fps. Please help. Thanks!