No, (extra) time required to process frames (compared to the average of your fps). While you may have 99% of all frames done within 10ms, which means you have high fps, the 1% may take longer. If those take too long you'll notice very small microstutters that happen ocassionally. However, gtx 970 sli does still well there, it's only a little less good than a Titan X in that regard.